A nurse holds a gun as she helps a wounded Pro-Russian gunmen to get out of the car in front of local hospital in Slovyansk, eastern Ukraine, Monday, May 5, 2014. Ukrainian troops fought pitched gun battles Monday with a pro-Russia militia occupying an eastern city пїЅ an apparent escalation of their efforts to bring the region back under government control. (Photo by Darko Vojinovic/AP Photo)

Pro-Russian armed men ride on top of an armoured personnel carrier near the town of Slaviansk, eastern Ukraine, May 5, 2014. Pro-Russian separatists ambushed Ukrainian forces on Monday, triggering heavy fighting on the outskirts of the rebel stronghold of Slaviansk, Interior Minister Arsen Avakov was quoted as saying. (Photo by Baz Ratner/Reuters)

Ukrainian soldiers stand at a checkpoint near the eastern Ukranian city of Slavyansk on May 5, 2014. Four Ukrainian troops were killed and 30 wounded in intense fighting around the rebel-held town of Slavyansk on May 5, the interior ministry said. The ministry added that the pro-Russian gunmen controlling the town were using civilians as human shields and were shooting from houses, some of which were on fire. It said there were civilian casualties but did not provide a toll. (Photo by Vasily Maximov/AFP Photo)

Pro-Russian gunmen hold their weapons as they try to block a military base of Ukrainian riot police in Donetsk, Ukraine, Tuesday, May 6, 2014. The pro-Russian insurgent gunmen surrounded the base and said they were holding negotiations with commanders inside to ensure that they did not join forces with government-allied groups. (Photo by Alexander Ermochenko/AP Photo)

A tram passes a portrait of Andriy Biryukov, a pro-Ukrainian activist killed in clashes on Friday, at his funeral in Odessa May 6, 2014. Pro-Russian rebels shot down a Ukrainian helicopter in fierce fighting near the eastern town of Slaviansk on Monday, and Kiev drafted police special forces to the southwestern port city of Odessa to halt a feared westward spread of rebellion. (Photo by Gleb Garanich/Reuters)

A pro-Russian gunman holds his weapon while guarding the local administration building in the center of Slovyansk, eastern Ukraine, Tuesday, May 6, 2014. Interior Minister Arsen Avakov gave the death toll on his Facebook page Tuesday, adding that 20 government troops were also injured during fighting in Slovyansk, a city of 125,000. It was not exactly clear when the deaths took place. Gunbattles around the city Monday were the interim government's most ambitious effort to date to quell weeks of unrest in Ukraine's mainly Russian-speaking east. (Photo by Darko Vojinovic/AP Photo)

Pro-Russian gunmen carry their weapons at the local administration building in the center of Slovyansk, Ukraine, Tuesday, May 6, 2014. Gunbattles took place at various positions around the city Monday in what has proven the most ambitious government effort to date to quell unrest in the mainly Russian-speaking east. (Photo by Alexander Zemlianichenko/AP Photo)

Relatives cry around the coffin of 17 year-old Vadim Papura during a religious service outside his apartment block, in Odessa, Ukraine, Tuesday May 6, 2014. Papura died after jumping out of the burning trade union building in an attempt to escape Friday's fire that killed most of the 40 people that died after riots erupted last Friday. (Photo by Vadim Ghirda/AP Photo)

An armed pro-Russian man stands at a checkpoint in the town of Slovyansk on May 6, 2014. (Photo by Baz Ratner/Reuters)

Ukrainian Prime Minister Arseniy Yatsenyuk, center, shake hands with a Ukrainian soldier at a block post on the road at Slovyansk, Ukraine, Wednesday, May 7, 2014. Ukrainian military operations that began Monday to expunge pro-Russia forces from the city of Slovyansk were the interim government's most ambitious effort so far to quell weeks of unrest in Ukraine's mainly Russian-speaking east. (Photo by Andrew Kravchenko/AP Photo)

The girlfriend of Andrei Brazhevskiy, a pro-Russian activist, cries during his funeral in Odessa, Ukraine, Wednesday, May 7, 2014. Brazhevskiy, 27, died after jumping out of the burning trade union building in an attempt to escape Friday's fire that killed most of the 40 people that died after riots erupted last Friday. (Photo by Vadim Ghirda/AP Photo)

Ukrainian Prime Minister Arseniy Yatsenyuk, right, shake hands with Ukrainian soldiers at a block post on the road at Slovyansk, Ukraine, Wednesday, May 7, 2014. Ukrainian military operations that began Monday to expunge pro-Russia forces from the city of Slovyansk were the interim government's most ambitious effort so far to quell weeks of unrest in Ukraine's mainly Russian-speaking east. (Photo by Andrew Kravchenko/AP Photo)

Relatives of detained pro-Russian activists clash with police officers in Mariupol, Ukraine, Wednesday, May 7, 2014. Angry pro-Russian protesters in the city of Mariupol in eastern Ukraine blocked police forces on Wednesday from moving at least 14 detained activists from a police station to face a judge as required by law. About 50 people, relatives of those detained, surrounded a police truck and stopped it from reaching the police station. (Photo by Alexander Ermochenko/AP Photo)

People take part in a training at a base of the National Guard of Ukraine near Kiev May 8, 2014. (Photo by Konstantin Grishin/Reuters)

Ukrainian politician and presidential candidate Yulia Tymoshenko (2nd L) visits a checkpoint near Kakhovskaya Hydroelectric Power Plant in Kherson region, May 8, 2014. (Photo by Alexander Prokopenko/Reuters)

An election worker at the Donetsk self-proclaimed republic's election commission arranges referendum materials inside the commission headquarters in Donetsk, eastern Ukraine May 8, 2014. Pro-Russian separatists in eastern Ukraine ignored a public call by Russian President Vladimir Putin to postpone a referendum on independence, declaring they would go ahead on May 11 with a vote that could lead to war. (Photo by Marko Djurica/Reuters)

A pro-Russian gunman atop a car patrols through the center of Slovyansk, eastern Ukraine, Thursday, May 8, 2014. A strong majority of Ukrainians want their country to remain a single, unified state and this is true even in the largely Russian-speaking east where a pro-Russia insurgency has been fighting for autonomy, a poll released Thursday shows. The survey results were released as the pro-Russia forces were considering whether to go ahead with a referendum on autonomy planned for Sunday in defiance of a call from Russian President Vladimir Putin to delay the vote. A decision was expected later in the day. (Photo by Darko Vojinovic/AP Photo)

The head of the elections commission of the so-called Donetsk People's Republic, Denis Pushilin, center foreground, is seen during a press conference to inform the media about the referendum at the occupied administration building in Donetsk, Ukraine, Thursday, May 8, 2014. Today, the pro-Russia insurgency in eastern Ukraine decided Thursday to go ahead with Sunday's referendum on autonomy despite a call from Russian President Vladimir Putin to delay it. (Photo by Manu Brabo/AP Photo)

The body of a Ukrainian policeman is seen covered on the ground outside police headquarters after an Ukrainian forces attempt to drive out pro-Russian militants in Mariupol May 9, 2014. Ukrainian security forces killed about 20 pro-Russian rebels who tried to seize control of police headquarters in the eastern port city of Mariupol on Friday, the Interior Minister said. (Photo by Marko Djurica/Reuters)

A Soviet-era car with a sign “Seventy years without war” drives past during a Victory Day military parade in Sevastopol, Crimea, Friday, May 9, 2014. Russian President Vladimir Putin extolled the return of Crimea to Russia before tens of thousands Friday during his first trip to Black Sea peninsula since its annexation. The triumphant visit was quickly condemned by Ukraine and NATO. (Photo by Ivan Sekretarev/AP Photo)

A woman shouts outside the burnt trade union building after Victory Day celebrations in Odessa, Ukraine, Friday, May 9, 2014. The local governor in the Black Sea port of Odessa, which last week was rocked by violent clashes between pro-Russian forces and supporters of the central government that left nearly 50 people died, issued an order banning the public display of Russian flags. (Photo by Vadim Ghirda/AP Photo)

Two women walk in front of the burned police headquarters in the southeastern port city of Mariupol May 9, 2014. Ukrainian forces attacked the police headquarters in Mariupol on Friday in an attempt to drive out pro-Russian militants, and the building caught fire, according to a Ukrainian parliamentary deputy. (Photo by Marko Djurica/Reuters)

People greet pro-Russian activists atop of a government forces armored personal carrier captured from the enemy in fighting in Mariupol, eastern Ukraine, Friday, May 9, 2014. Fighting exploded Friday in Mariupol, a city of 500,000 on the Sea of Azov that is on the main road between Russia proper and Crimea. The fighting between government forces and insurgents in Mariupol has left several people dead. (Photo by Alexander Zemlianichenko/AP Photo)

A pro-Russian gun man holds his machine gun and a flower during the commemoration of Victory Day in Donetsk, Ukraine, Friday, May 9, 2014. Victory Day honors the armed forces and the millions who died in World War II. This year it comes as Russia is locked in the worst crisis with the West, over Ukraine, since the end of the Cold War. (Photo by Manu Brabo/AP Photo)

A masked man jumps over a burning barricade in front of the police headquarters in the southeastern port city of Mariupol May 9, 2014. Ukrainian forces attacked the police headquarters in Mariupol on Friday in an attempt to drive out pro-Russian militants, and the building caught fire, according to a Ukrainian parliamentary deputy. (Photo by Marko Djurica/Reuters)

A man looks at a dead body after Ukrainian forces attacked police headquarters in an attempt to drive out pro-Russian militants in Mariupol May 9, 2014. Ukrainian security forces killed about 20 pro-Russian rebels who tried to seize control of police headquarters in the eastern port city of Mariupol on Friday, the Interior Minister said. (Photo by Marko Djurica/Reuters)

People pass by a broken armoured vehicle left behind after Ukrainian forces attacked police headquarters in an attempt to drive out pro-Russian militants in Mariupol May 9, 2014. (Photo by Marko Djurica/Reuters)

Fire fighters tackle the blaze in the Mariupol police station, Ukraine, 09 May 2014. Two eastern Ukrainian provinces will go ahead with a referendum on seceding from the country as planned this weekend despite Russian President Vladimir Putin's call for a delay, separatist leaders told Russia's Interfax news agency on 08 May. “The referendum on May 11 will take place”, said Miroslav Rudenko, a separatist leader of the self-proclaimed Donetsk People's Republic. The secession referendum will let the three million residents of the provinces of Luhansk and Donetsk vote on whether they want to stay part of Ukraine. Ukrainians opposed to a split see it as a precursor to an eventual merger with Russia, as happened with Crimea in March. (Photo by Alexey Furman/EPA)

People carry a firefighter injured during an attack at a police station in Mariupol, eastern Ukraine, Friday, May 9, 2014. Fighting between government forces and insurgents in Mariupol has left several people dead. (Photo by Evgeniy Maloletka/AP Photo)

A man celebrates as a broken armoured vehicle left behind by Ukrainian forces is taken away by pro-Russian militants in Mariupol May 9, 2014. Ukrainian security forces killed about 20 pro-Russian rebels who tried to seize control of police headquarters in the eastern port city of Mariupol on Friday, the Interior Minister said. (Photo by Marko Djurica/Reuters)

A woman walks past a burning barricade near the city hall in Mariupol, on May 10, 2014. (Photo by Marko Djurica/Reuters)

A masked pro Russia man is seen atop an APC flying a Russian flag, top, and a Donetsk People's Republic flag, as it stands in front of the occupied administration building in Donetsk, Ukraine, Saturday, May 10, 2014. Two restive regions in eastern Ukraine are preparing to vote on declaring sovereignty and ceding from Ukraine, in a referendum on Sunday in the Donetsk and Luhansk regions, where pro-Russia insurgents have seized government buildings and clashed with police and Ukrainian troops. (Photo by Manu Brabo/AP Photo)

People stand on top of burnt-out armoured personal carrier near the city hall in Mariupol, eastern Ukraine May 10, 2014. At least seven people were killed and dozens wounded in clashes in the port city on Friday, two days before a referendum on self-rule that threatens to plunge the country into civil war. (Photo by Marko Djurica/Reuters)

An effigy of a Ukrainian soldier, with a sign that reads “Welcome to Slovyansk”, hangs over a pro-Russian barricade on the outskirts of the eastern Ukrainian town, on May 10, 2014. (Photo by Yannis Behrakis/Reuters)

Armed pro-Russian militants stand guard at their checkpoint alongside a railway line in Slovyansk, on May 10, 2014. (Photo by Roman Pilipey/EPA)

A pro-Russia rebel sits on top of an armored vehicle outside a regional government building in Donetsk, eastern Ukraine May 10, 2014. (Photo by Marko Djurica/Reuters)

People attempt to drive a commandeered armored personnel carrier a day after deadly clashes on May 10, 2014 in Mariupol, Ukraine. A referendum on greater autonomy is planned for the region tomorrow. (Photo by Brendan Hoffman/Getty Images)

An elderly man brandishes his passport at the camera, with it's cover bearing a former Soviet Union sign, near to barricades at the Ukrainian regional office of the Security Service ahead of the regional referendum in the eastern Ukraine city of Luhansk on Saturday May 10, 2014. (Photo by Igor Golovniov/AP Photo)

Pro-Russian activists deliver election materials to polling stations in Slovyansk, Ukraine, on May 10, 2014. Preparations were being made for Sunday's sovereignty referendum planned by pro-Russian separatists in eastern Ukraine. (Photo by John Moore/Getty Images)

Voters in Moscow hold their Ukrainian passports as they wait to enter a polling station, on May 11, 2014. Separatist leaders in eastern Ukraine have in the past come out clearly in favor of independence or of union with Russia, and they have suggested that another referendum to decide that question could take place later. Russia is almost certain to embrace Sunday’s vote as legitimate. (Photo by Sergei Karpukhin/Reuters)

People wait in line at a polling station in the center of Slovyansk, eastern Ukraine, Sunday, May 11, 2014. Residents of two restive regions in eastern Ukraine engulfed by a pro-Russian insurgency are casting ballots in contentious and hastily organized independence referenda. Sunday's ballots seek approval for declaring so-called sovereign people's republics in the Donetsk and Luhansk regions, where rebels have seized government buildings and clashed with police and Ukrainian troops. (Photo by Darko Vojinovic/AP Photo)

In the eastern Ukrainian city of Mariupol, voters wait to receive ballots from members of the local election commission, on May 11, 2014. (Photo by Marko Djurica/Reuters)

A woman is led aside as her partner is detained by Ukrainian security forces for being aggressive at an army checkpoint in the southeastern port city of Mariupol, on May 11, 2014. Residents’ attitudes appear to have hardened considerably with the deaths of dozens of pro-Russian activists in the city of Odessa this month and with reports that troops fired at a crowd in Mariupol last week. (Photo by Marko Djurica/Reuters)

A woman cries after her partner is detained by Ukrainian security forces for being aggressive at an army checkpoint, on May 11, 2014. (Photo by Marko Djurica/Reuters)

A Ukrainian soldier aims his rifle at an army checkpoint during a referendum on self-rule in the southeastern port city of Mariupol, May 11, 2014. (Photo by Marko Djurica/Reuters)

Ukrainian soldiers burn referendum ballot slips that they said were falsified and seized from a car at a checkpoint in Mariupol, on May 11, 2014. Many observers said the referendum lacks credibility, that names were checked against a 2012 voters’ list but that anyone who turned up with a passport was allowed to vote, even if they weren’t on the list. At one polling station in Mariupol, many people brought multiple passports on behalf of relatives and openly filled out two, three or even four ballot slips themselves, observers said. (Photo by Marko Djurica/Reuters)

A voter casts a ballot during a referendum on the status of the Donetsk region in the eastern Ukrainian city of Slaviansk May 11, 2014. Ukrainian leader Oleksander Turchinov warned pro-Russian eastern regions they would be stepping into the abyss if they voted for self-rule on Sunday in a referendum that has raised Western fears of a slide to full civil war. (Photo by Baz Ratner/Reuters)

An armed pro-Russian activists stands guard near a polling booth during the referendum called by pro-Russian rebels to split from the rest of Ukraine, on May 11, 2014 in Donetsk. (Photo by Alexander Khudoteply/AFP Photo)

An armed pro-Russian activists stands guard as a woman casts her ballot for the referendum called by pro-Russian rebels to split from the rest of Ukraine, on May 11, 2014 in Donetsk. The vote, carried out as two “referendums” in provinces where the insurgents hold more than a dozen towns, marks a serious deepening of the political crisis in Ukraine, which has pushed East-West relations to lows not seen since the end of the Cold War. (Photo by Alexander Khudoteply/AFP Photo)

An Ukrainian woman and her son, who are in Russia at the moment, cast a referendum ballot in Moscow, Russia, on Sunday, May 11, 2014. Residents of two restive regions in eastern Ukraine cast ballots Sunday in referendums, which seek approval for declaring sovereign people's republics in the Donetsk and Luhansk regions. Many of Ukrainians living in Moscow came to vote as well. (Photo by Dmitry Lovetsky/AP Photo)

Ukrainian people reflected in the a window with a banner reading “Say Republic yes – 11 May” stand in line for voting at a polling station in Donetsk, Ukraine, 11 May 2014. Residents of eastern Ukraine began voting on an independence referendum that was organized by pro-Russian separatists and rejected by the government in Kiev. Russian-speakers and supporters of Moscow have been rallying in the region since March, when a referendum on independence led to Russia's annexation of Crimea. (Photo by Maxim Shipenkov/EPA)

Local residents watch as others give first aid to a man who was shot in the leg by Ukranian militia in the village of Krasnoarmisk, Ukraine, 11 May 2014. Eyewitness said that Ukranian militia tried to stop the referendum voters briefly taking the City Hall of Krasnoarmisk, where unarmed pro-Russian supporters were gathering. Reportedly the Ukranian militia came out out the building and started shooting at the people, killing at least one man and leaving at least two others injured. (Photo by EPA/Maysun)

A gunman stands guard as local residents walk from a polling station in Slovyansk, eastern Ukraine, Sunday, May 11, 2014. Residents of two restive regions in eastern Ukraine engulfed by a pro-Russian insurgency cast votes Sunday in contentious and hastily organized independence referendums, which have been rejected as illegal by the Ukrainian government and the West. (Photo by Alexander Zemlianichenko/AP Photo)

A local commission member issues ballots at a polling station in Luhansk, Ukraine, on Sunday May 11, 2014. Residents of two restive regions in eastern Ukraine cast ballots Sunday in referendums, which seek approval for declaring sovereign people's republics in the Donetsk and Luhansk regions. (Photo by Evgeniy Maloletka/AP Photo)

A local resident casts her ballots at a polling station in Luhansk, Ukraine, on Sunday May 11, 2014. Residents of two restive regions in eastern Ukraine cast ballots Sunday in referendums, which seek approval for declaring sovereign people's republics in the Donetsk and Luhansk regions. (Photo by Evgeniy Maloletka/AP Photo)

A couple kisses outside the occupied regional administration building, which serves as headquarters for pro-Russian separatists, on May 11, 2014 in Donetsk, Ukraine. A referendum on greater autonomy is being held after pro-Russian activists took over at least ten cities in the eastern part of the country in a bid for less control from the central government from Kiev. (Photo by Brendan Hoffman/Getty Images)

A man reacts next to the body of a pro-Russia man in Krasnoarmeisk, Ukraine, Sunday, May 11, 2014. (Photo by Manu Brabo/AP Photo)

A woman casts a shadow on leaving a booth to cast her ballot at a polling station in Luhansk, Ukraine, on May 11, 2014. (Photo by Evgeniy Maloletka/Associated Press)

A Cossack militiaman guards a polling station in the center of Slovyansk, eastern Ukraine, Sunday, May 11, 2014. Residents of two restive regions in eastern Ukraine engulfed by a pro-Russian insurgency are casting ballots in contentious and hastily organized independence referenda. Sunday's ballots seek approval for declaring so-called sovereign people's republics in the Donetsk and Luhansk regions, where rebels have seized government buildings and clashed with police and Ukrainian troops. (Photo by Darko Vojinovic/AP Photo)

A woman reacts after Ukrainian national guardsmen opened fire on a crowd outside a town hall in Krasnoarmeisk, about 30 kilometers (20 miles) from the regional capital, Donetsk, Ukraine, Sunday, May 11, 2014. Although the voting in the Donetsk and Luhansk regions appeared mostly peaceful, Ukrainian national guardsmen opened fire on a crowd outside a town hall in Krasnoarmeisk, and an official with the region’s insurgents said there were fatalities. (Photo by Manu Brabo/AP Photo)

People queue to the polling stations during a so-called referendum in the eastern Ukrainian city of Donetsk on May 11, 2014. Voting began Sunday in referendums called by pro-Russian rebels in eastern Ukraine to split from the rest of the ex-Soviet republic, polls the US slammed as “illegal” amid fears they could spark civil war. The vote, carried out as two “referendums” in provinces where the insurgents hold more than a dozen towns, marks a serious deepening of the political crisis in Ukraine, which has pushed East-West relations to lows not seen since the end of the Cold War. (Photo by Genya Savilov/AFP Photo)

An Effigy depicting a representative of the Kiev authorities is hung over a barricade in the eastern Ukranian city of Slavyansk on May 11, 2014, on the day of the referendum called by pro-Russian rebels in eastern Ukraine to split from the rest of the ex-Soviet republic, in Slavyansk on May 11, 2014. (Photo by Vasily Maximov/AFP Photo)

An Armoured Personnel Carrier (APC) with a Russian flag drives through the center of Slaviansk during the day of referendum organized by the so-called Donetsk People's Republic members, in Slaviansk, Ukraine, 11 May 2014. Residents of eastern Ukraine on 11 May were voting in an independence referendum that was organized by pro-Russian separatists and rejected by the government in Kiev. Russian-speakers and supporters of Moscow have been rallying in the region since March, when a referendum on independence led to Russia's annexation of Crimea. The pro-Russian organizers of the referendum were pushing ahead with the vote despite Russian President Vladimir Putin had appealed them to postpone it. (Photo by Roman Pilipey/EPA)