Battle for Donetsk

A heavily armed pro-Russian rebel mans a newly erected barricade on the airport road of the eastern Ukrainian city of Donetsk May 27, 2014. REUTERS/Yannis Behrakis

A boy walks by as firefighters attempt to extinguish a fire at the sports arena "Druzhba" (Friendship), which is the home venue of the ice hockey club "Donbass", in Donetsk, May 27, 2014. REUTERS/Stringer

A heavily armed pro-Russian rebel mans a newly erected barricade on the airport road of the eastern Ukrainian city of Donetsk May 27, 2014. REUTERS/Yannis Behrakis

A couple walks past a wrecked Kamaz truck as they flee an area near the Donetsk airport May 27, 2014. REUTERS/Yannis Behrakis

A bloodstained icon of Jesus is seen among shattered glass atop a wrecked Kamaz truck near the Donetsk airport May 27, 2014. REUTERS/Yannis Behrakis

A pro-Russian rebel armed with an anti-tank weapon mans a newly erected barricade along the airport road of the eastern Ukrainian city of Donetsk May 27, 2014. REUTERS/Yannis Behrakis

People stand near belongings of separatists killed in a fight with pro-Ukrainian forces outside a morgue in Donetsk May 27, 2014. REUTERS/Maxim Zmeyev

Locals stand by a wrecked Kamaz truck near the Donetsk airport May 27, 2014. REUTERS/Yannis Behrakis

A pool of blood is seen on the tarmac next to a wrecked military truck near the Donetsk airport May 27, 2014. REUTERS/Yannis Behrakis

A local takes photos of a wrecked Kamaz truck near the Donetsk airport May 27, 2014. REUTERS/Yannis Behrakis

A Ukrainian helicopter Mi-24 gunship fires its cannons against rebels at the main terminal building of Donetsk international airport May 26, 2014. REUTERS/Yannis Behrakis

A military truck with armed pro-Russian militants drives through a police check-point towards the airport of the eastern Ukrainian city of Donetsk May 26, 2014. REUTERS/Yannis Behrakis

A local and a news photographer run for cover near Donetsk international airport during heavy fighting May 26, 2014. REUTERS/Yannis Behrakis

A Ukrainian helicopter Mi-24 gunship fires decoy flares over a residential area moments after attacking Donetsk international airport May 26, 2014. REUTERS/Yannis Behrakis

A family takes shelter in a building near Donetsk international airport during heavy fighting May 26, 2014. REUTERS/Yannis Behrakis

Unidentified men are seen in front of a sign directing traffic to Donetsk's International airport at the eastern Ukrainian city of Donetsk May 26, 2014. REUTERS/Yannis Behrakis

A rebel takes cover in a building near Donetsk international airport during heavy fighting May 26, 2014. REUTERS/Yannis Behrakis

Smoke billows from Donetsk international airport during heavy fighting between Ukrainian and pro-Russian forces May 26, 2014. REUTERS/Yannis Behrakis

People run for cover near Donetsk international airport during heavy fighting May 26, 2014. REUTERS/Yannis Behrakis

Smoke billows behind the main terminal of Donetsk international airport during heavy fighting between Ukrainian and pro-Russian forces May 26, 2014. REUTERS/Yannis Behrakis

Smoke rises from Donetsk international airport during heavy fighting between Ukrainian and pro-Russian forces May 26, 2014. REUTERS/Maxim Zmeyev

Passengers and their suitcases are seen at a blocked junction close to the airport at the eastern Ukrainian city of Donetsk May 26, 2014. REUTERS/Yannis Behrakis

The air traffic control tower of Donetsk international airport is seen in the eastern Ukrainian city of Donetsk May 26, 2014.REUTERS/Yannis Behrakis

The terminal of Donetsk international airport is seen behind a cemetery at the eastern Ukrainian city of Donetsk May 26, 2014. REUTERS/Yannis Behrakis