A Ukrainian serviceman wearing a new year's hat waves at his comrades while standing beside his tank near Debaltseve, eastern Ukraine, February 8, 2015. (Photo by Gleb Garanich/Reuters)

Actress with the Donbass Opera Theatre prepares to perform Eugene Onegin in Donetsk, Ukraine, Saturday, February 7, 2015. For the few dozen spectators that turn up, the weekly performances at the city's opera house serve as a respite from the war raging outside between Russian-backed separatists and Ukrainian government forces. (Photo by Petr David Josek/AP Photo)

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 woman begs Ukrainian President Petro Poroshenko to stop the bombing in Donetsk after shell hit the residential area where she lives, killing two civilians in Donetsk's Kyibishevsky district, on January 29, 2015. (Photo by Manu Brabo/AFP Photo)

Rescue workers try to pull out a piece of an exploded Grad missile outside an apartment building in Vostochniy district of Mariupol, Eastern Ukraine, Sunday, January 25, 2015. Indiscriminate rocket fire slammed into a market, schools, homes and shops Saturday in Ukraine's southeastern city of Mariupol, killing at least 30 people, authorities said. The Ukrainian president called the blitz a terrorist attack and NATO and the U.S. demanded that Russia stop supporting the rebels. (Photo by Evgeniy Maloletka/AP Photo)

People look through the front windshield of a damaged trolleybus in Donetsk, January 22, 2015. At least seven civilians were killed on Thursday when a shell or a mortar hit a trolleybus stop in the rebel-controlled city of Donetsk in eastern Ukraine, a Reuters witness said. The Reuters cameraman said he saw six bodies on the ground near, and inside, a trolleybus in a southern district of the city. Windows of shops nearby had been blown out by the blast. (Photo by Alexander Ermochenko/Reuters)

Ukrainians swim in an ice hole as part of the celebration of the Epiphany in Kiev, Ukraine, Monday, January 19, 2015. Orthodox believers celebrate the holiday of the Epiphany on Jan. 19, and traditionally bathe in holes cut through thick ice on rivers and ponds to cleanse themselves with water deemed holy for the day. (Photo by Sergei Chuzavkov/AP Photo)

Ukrainian servicemen sit atop an armored personnel carrier (APC) at a military base in the town of Kramatorsk, eastern Ukraine, December 24, 2014. (Photo by Valentyn Ogirenko/Reuters)