A pro-Russian rebel guards a captured former Ukrainian Army checkpoint outside Vuhlehirsk, Donetsk region, eastern Ukraine, Thursday, February 5, 2015. The rebels have closed in around the town in a strategy they triumphantly refer to as the Debaltseve cauldron. Separatists recently burst through government lines in the rural settlement of Vuhlehirsk. (Photo by Vadim Braydov/AP Photo)

A Ukrainian tank is seen near the eastern Ukrainian town of Debaltseve, February 5, 2015. (Photo by Gleb Garanich/Reuters)

A resident covers the window of his apartment with a plastic sheet inside a residential block, that was damaged by a shelling on Wednesday according to locals, in Donetsk, February 5, 2015. (Photo by Maxim Shemetov/Reuters)

Local residents wait to board a bus to flee the conflict in Debaltseve, eastern Ukraine, February 5, 2015. (Photo by Gleb Garanich/Reuters)

Local residents flee the conflict in Debaltseve, eastern Ukraine, February 5, 2015. (Photo by Gleb Garanich/Reuters)

Ukrainian army soldiers perform a weapons exercise at a training ground outside Lviv, western Ukraine, Thursday, February 5, 2015. The Ukrainian government is anxious to use Thursday's visit by U.S. Secretary of State John Kerry to Kiev to reiterate its plea for lethal aid. President Barack Obama has opposed the idea of sending weapons to Ukraine but sources in his administration say this position could change in the light of recent events. (Photo by Pavlo Palamarchuk/AP Photo)

A municipal official looks through the window of a residential block, which was damaged by a shelling on Wednesday according to locals, in Donetsk, February 5, 2015. (Photo by Maxim Shemetov/Reuters)

A member of the armed forces of the separatist self-proclaimed Donetsk People's Republic looks on near a building destroyed during battles with the Ukrainian armed forces in Vuhlehirsk, Donetsk region, February 4, 2015. (Photo by Maxim Shemetov/Reuters)

Local residents wait to board a bus to flee the conflict in Debaltseve, eastern Ukraine, February 5, 2015. (Photo by Gleb Garanich/Reuters)

Members of the armed forces of the separatist self-proclaimed Donetsk People's Republic gather at a checkpoint in Vuhlehirsk, Donetsk region, February 4, 2015. (Photo by Maxim Shemetov/Reuters)

A tank of the separatist self-proclaimed Donetsk People's Republic is seen near Yenakiieve, Donetsk region, February 4, 2015. (Photo by Maxim Shemetov/Reuters)

A child draws near her house in Debaltseve, eastern Ukraine, February 5, 2015. (Photo by Gleb Garanich/Reuters)

A member of the armed forces of the separatist self-proclaimed Donetsk People's Republic holds up a large-caliber bullet for the camera in Vuhlehirsk, Donetsk region, February 4, 2015. (Photo by Maxim Shemetov/Reuters)

Pro-Russian separatists ride on a tank in Donetsk, eastern Ukraine, February 1, 2015. (Photo by Maxim Shemetov/Reuters)

Men load the body of a victim of shelling into a vehicle at a site hit by shelling in Donetsk, eastern Ukraine, February 1, 2015. (Photo by Maxim Shemetov/Reuters)

A woman looks out of the window of a residential block damaged by a shelling in Donetsk, eastern Ukraine, February 1, 2015. (Photo by Maxim Shemetov/Reuters)

A woman with a child walks past crosses with the names of victims who were killed in the shelling of the government-held port of Mariupol by pro-Russian rebels on January 24, during a protest against Russia's actions in Donetsk region in front of Russian embassy in Kiev, February 1, 2015. (Photo by Valentyn Ogirenko/Reuters)

People attend a funeral ceremony for Vadym Zherebylo, a member of the self-defence battalion “Aydar”, who was killed in the fighting in Luhansk region in eastern Ukraine, at the Independence Square in central Kiev February 2, 2015. (Photo by Valentyn Ogirenko/Reuters)

People attend a funeral ceremony for Vadym Zherebylo, a member of self-defence battalion “Aydar”, who was killed in the fighting in Luhansk region in eastern Ukraine, at Independence Square in central Kiev February 2, 2015. (Photo by Valentyn Ogirenko/Reuters)

A serviceman from the battalion “Aydar” throws a tyre on a fire during a protest against disbanding of the battalion in front of Ukraine's Defence Ministry in Kiev, February 2, 2015. (Photo by Valentyn Ogirenko/Reuters)

An elderly Orthodox priest shouts as fighters of the “Aydar” Ukrainian volunteer battalion, burn tyres at the entrance to the Ukrainian Defence Ministry in Kiev, on February 2, 2015 during an action to prevent the possible disbandment of their battalion. (Photo by Sergei Supinsky/AFP Photo)

Volunteers of the “Aidar” battalion burn tires in front of the Ministry of Defense as they protest against a decision to change the leadership of the battalion in Kiev, Ukraine, Monday, February 2, 2015. The “Aidar” battalion, a volunteer force, and the Defense Minister have agreed that the battalion will be divided into two units. Both of them – one headed by the old leader – will be incorporated into the Defense Ministry and will continue fighting in the country's east against pro-Russian separatists. (Photo by Sergei Chuzavkov/AP Photo)

A Ukrainian serviceman guarding Ukraine's Defence Ministry is helped up by his colleagues after failing to arrest a member of the “Aydar” battalion who entered the ministry compound, during a protest against the disbanding of the battalion in Kiev February 2, 2015. (Photo by Valentyn Ogirenko/Reuters)

A woman stands in her house, which was damaged by recent shelling, in central Donetsk, eastern Ukraine, February 2, 2015. (Photo by Alexander Ermochenko/Reuters)

A woman reacts as she looks at the debris inside a flat at a residential block damaged by a recent shelling in Yenakieve town, northeast from Donetsk, February 2, 2015. (Photo by Maxim Shemetov/Reuters)

A woman reacts as she stands near a multi-storey block of flats damaged by shelling in Yenakieve town, northeast from Donetsk, February 2, 2015. (Photo by Maxim Shemetov/Reuters)

A man stands in a flat at a residential block damaged by a recent shelling in Yenakieve town, northeast from Donetsk, February 2, 2015. (Photo by Maxim Shemetov/Reuters)

Women stand near a multi-storey block of flats damaged by shelling in Yenakieve town, northeast from Donetsk, February 2, 2015. (Photo by Maxim Shemetov/Reuters)

Local residents leave a residential block during a recent shelling, in the town of Yenakieve, northeast from Donetsk, February 2, 2015. (Photo by Maxim Shemetov/Reuters)

A pro-Russian separatist checks a driver's documents in Zhdanivka town, northeast from Donetsk, February 2, 2015. (Photo by Maxim Shemetov/Reuters)

Alexander Zakharchenko (R), leader of the self-proclaimed Donetsk People's Republic (DPR), and Igor Plotnitsky, leader of the self-proclaimed Luhansk People's Republic (LPR), attend a news conference in Donetsk February 2, 2015. (Photo by Maxim Shemetov/Reuters)

Yabloko (Apple) political party leader Sergei Mitrokhin (L) attends a rally in support of Svetlana Davydova, who was detained on suspicion of treason, as a policeman checks the documents of participants near the Federal Security Service headquarters in central Moscow, February 3, 2015. Nine months after Russian activist Svetlana Davydova called the Ukrainian embassy in Moscow to warn that Russian soldiers were making their way to Ukraine, an investigator with an order for her arrest showed up at her door. Her husband, Anatoly Gorlov, said the investigator from the Federal Security Service (FSB), the successor to the Soviet KGB, detained Davydova, a mother of seven living in the western Russian city of Vyazma, on suspicion of treason. The placard reads: “Freedom to Svetlana Davydova!”. (Photo by Sergei Karpukhin/Reuters)

Svetlana Davydova, center, a mother of seven, who lives in the city of Vyazma in western Russia and was arrested last month on treason charges for providing Ukraine with information on Russian troops movements, walks with two unidentified men after she was released for a prison in Moscow, Russia, Tuesday, February 3, 2015. The husband of a Russian mother of seven suspected of spying for Ukraine said Tuesday he was summoned for questioning but refused to answer any questions, as pressure grew on the Kremlin to release her. (Photo by Pavel Golovkin/AP Photo)

Russian activist Svetlana Davydova (2nd R), her husband Anatoly Gorlov (L) and children Spartak (2nd R), Kassandra (3rd L), Eduard (R) and Artur pose for a picture in Vyazma, February 4, 2015. Russia has conditionally released an activist accused of high treason for phoning the Ukrainian embassy in Moscow to warn that Russian soldiers might be heading to eastern Ukraine, her husband said on February 3. Gorlov told Reuters by telephone that Davydova was on her way home. But Davydova, who is bringing up seven children with her husband, will have her movements restricted and still faces up to 20 years in jail if convicted in a trial. (Photo by Maxim Zmeyev/Reuters)

An elderly woman collects water from a puddle in Debaltseve, February 3, 2015. (Photo by Sergey Polezhaka/Reuters)

Workers from Rinat Akhmetov's Foundation sort humanitarian aid at Donbass Arena stadium in Donetsk February 3, 2015. (Photo by Maxim Shemetov/Reuters)

People sit inside a bus before the departure, as they flee due to the military conflict, in Debaltseve, February 3, 2015. (Photo by Sergey Polezhaka/Reuters)

Pro-Russian rebels drive a self-propelled anti-aircraft system Strela-10 in Donetsk February 3, 2015. (Photo by Maxim Shemetov/Reuters)

A woman picks up a bag with humanitarian aid in front of a delivery point in Donetsk February 3, 2015. (Photo by Maxim Shemetov/Reuters)

A woman walks to cook on a fire outside her house in Debaltseve, February 3, 2015. (Photo by Sergey Polezhaka/Reuters)

A member of the Ukrainian armed forces offers local residents to join people who are boarding a bus and fleeing from military conflict in Debaltseve, February 3, 2015. (Photo by Sergey Polezhaka/Reuters)

People walk outside a house, which according to locals was recently damaged by shelling, in Donetsk February 3, 2015. (Photo by Alexander Ermochenko/Reuters)

A boy jumps over a puddle near Soviet-era hammer and sickle sculptures at a residential sector affected by shelling in Mariupol, a city on the Sea of Azov, eastern Ukraine February 3, 2015. (Photo by Gleb Garanich/Reuters)

A vendor sells soybean milk on a street at a residential sector affected by shelling in Mariupol, a city on the Sea of Azov, eastern Ukraine February 3, 2015. (Photo by Gleb Garanich/Reuters)

Members of the newly created Ukrainian interior ministry battalion “Saint Maria” take part in a ceremony before heading to military training, in front of St. Sophia Cathedral, in Kiev, February 3, 2015. Members of the battalion will be sent to the frontline in eastern regions of Ukraine shortly after the training, according to their commander. (Photo by Valentyn Ogirenko/Reuters)

A woman embraces a member of the newly created Ukrainian interior ministry battalion “Saint Maria” after a ceremony before they head to military training, in front of St. Sophia Cathedral, in Kiev, February 3, 2015. (Photo by Valentyn Ogirenko/Reuters)

A man speaks on the phone next to the body of a victim, near a hospital in Donetsk February 4, 2015. A shell hit a hospital in the east Ukrainian rebel-controlled city of Donetsk on Wednesday, killing or injuring several people, the city administration said. (Photo by Maxim Sergeev/Reuters)

A local resident removes broken glass from a window inside a building near a hospital in Donetsk February 4, 2015. (Photo by Maxim Sergeev/Reuters)

A local resident surveys damage done to a hospital in Donetsk February 4, 2015. At least two shells landed near a hospital in the separatist-controlled eastern Ukrainian city of Donetsk on Wednesday, killing at least three people nearby, a Reuters eyewitness said. (Photo by Maxim Shemetov/Reuters)

A woman reacts outside a damaged hospital in Donetsk February 4, 2015. (Photo by Maxim Shemetov/Reuters)

Members of the Ukrainian armed forces gather along a street, with dogs seen nearby, in Debaltseve, February 4, 2015. (Photo by Sergey Polezhaka/Reuters)

An elderly woman reacts while sitting with a child inside a bus before the departure as people flee due to a military conflict in Debaltseve, February 4, 2015. (Photo by Sergey Polezhaka/Reuters)

A local resident cooks outside her house in Debaltseve, February 4, 2015. (Photo by Sergey Polezhaka/Reuters)

A multiple rocket launcher system of the Ukrainian armed forces is seen behind bushes on the outskirts of Artemivsk, Donetsk region, February 4, 2015. (Photo by Sergey Polezhaka/Reuters)

Members of the armed forces of the separatist self-proclaimed Donetsk People's Republic walk near a building destroyed during battles with the Ukrainian armed forces in Vuhlehirsk, Donetsk region, February 4, 2015. (Photo by Maxim Shemetov/Reuters)

Members of the armed forces of the separatist self-proclaimed Donetsk People's Republic gather near an armoured vehicle destroyed during battles with the Ukrainian armed forces in Vuhlehirsk, Donetsk region, February 4, 2015. (Photo by Maxim Shemetov/Reuters)

Members of the armed forces of the separatist self-proclaimed Donetsk People's Republic gather near a burnt armoured vehicle in Vuhlehirsk, Donetsk region, February 4, 2015. (Photo by Maxim Shemetov/Reuters)

An armoured vehicle and a building, destroyed during battles between the armed forces of the separatist self-proclaimed Donetsk People's Republic and the Ukrainian armed forces, are seen in Vuhlehirsk, Donetsk region, February 4, 2015. (Photo by Maxim Shemetov/Reuters)

Members of the armed forces of the separatist self-proclaimed Donetsk People's Republic gather near a building destroyed during battles with the Ukrainian armed forces in Vuhlehirsk, Donetsk region, February 4, 2015. (Photo by Maxim Shemetov/Reuters)

Members of the separatist self-proclaimed Donetsk People's Republic drive armoured vehicles, with Saint George slaying the Dragon displayed on a red flag, near Yenakiieve, Donetsk region, February 4, 2015. The coat of arms of the Russian capital Moscow depicts St. George the Victorious atop a silver horse slaying a black dragon with silver harness, according to the official web site of Moscow city government. (Photo by Maxim Shemetov/Reuters)

A row of trucks of the separatist self-proclaimed Donetsk People's Republic is seen in Makiivka, Donetsk region, February 4, 2015. (Photo by Maxim Shemetov/Reuters)

People walk out of a building near damaged pavement following a shelling, according to locals, in Donetsk February 4, 2015. (Photo by Maxim Shemetov/Reuters)

Women stand next to the sculptures of (R-L) Soviet dictator Josef Stalin, U.S. President Franklin Roosevelt and British Prime Minister Winston Churchill, made by Zurab Tsereteli, during its opening ceremony in the settlement of Livadia, Yalta region, Crimea, February 5, 2015. The three-ton bronze composition depicting the partners of the anti-Hitler coalition was installed in Yalta, where the three leaders met for talks on February 4-11, 1945, local media reported. (Photo by Pavel Rebrov/Reuters)

People wait on a bus to leave the town of Debaltseve in Artemivsk, Ukraine, Tuesday, February 3, 2015. Since the unrest in eastern Ukraine surged anew in early January, the separatists have made notable strides in clawing territory away from the government in Kiev. Their main offensive is now directed at Debaltseve – a government-held railway junction once populated by 25,000 people that lies between the rebel-held cities of Luhansk and Donetsk. Almost 2,000 residents have fled in the last few days alone. (Photo by Petr David Josek/AP Photo)

A child waits on a bus to leave the town of Debaltseve in Artemivsk, Ukraine, Tuesday, February 3, 2015. (Photo by Petr David Josek/AP Photo)

A Ukrainian serviceman holds his position in an APC near Artemivsk, eastern Ukraine, Thursday, February 5, 2015. Fighting between Russia-backed separatists and Ukrainian forces in eastern Ukraine surged in January, raising the death toll to over 5,300 people killed since April. In a new push for peace, the leaders of France and Germany headed Thursday to Kiev and Moscow with a proposal to end the fighting in eastern Ukraine. (Photo by Evgeniy Maloletka/AP Photo)

In this screen shot made available by RU-RTR, pro-Russia rebels cover a body of a victim outside clinic 27, damaged after shelling, in Donetsk, Ukraine, Wednesday, February 4, 2015. Heavy shelling in the rebel stronghold of Donetsk in eastern Ukraine on Wednesday afternoon killed at least five people and damaged a hospital, six schools and five kindergartens, local officials said. (Photo by AP Photo/RU-RTR)

An elderly man is helped to board a bus to leave the town of Debaltseve in Artemivsk, Ukraine, Tuesday, February 3, 2015. (Photo by Petr David Josek/AP Photo)

In this screen shot made available by RU-RTR, pro-Russia rebels stand outside clinic 27, damaged after shelling, in Donetsk, Ukraine, Wednesday, February 4, 2015. (Photo by AP Photo/RU-RTR)

A Ukrainian multiple rocket launcher system BM-21 “Grad” is driven on a road near Artemivsk, eastern Ukraine, Thursday, February 5, 2015. (Photo by Evgeniy Maloletka/AP Photo)

A young man waits on a bus to leave the town of Debaltseve in Artemivsk, Ukraine, Tuesday, February 3, 2015. (Photo by Petr David Josek/AP Photo)

A Ukrainian army vehicle drives through fields near the town of Debaltseve, Ukraine, Monday, February 2, 2015. As fighting intensifies between government and rebel forces for control over a key railway hub in the eastern Ukraine town of Debaltseve, separatist leader Alexander Zakharchenko said Monday that he plans to mobilize enough new volunteers to bring his forces to 100,000 men. (Photo by Petr David Josek/AP Photo)

A woman cries near the body of her son, killed during a shelling at the hospital of Donetsk's Tekstilshik district, on Febuary 4, 2015. At least 12 people were killed in fighting between soldiers and pro-Russian separatists in east Ukraine, including four civilians who died when a hospital was hit in rebel stronghold Donetsk today. (Photo by Dominique Faget/AFP Photo)