Relatives mourn near the coffin of Mark Zverev, a taxi driver shot dead on May 26, 2014 during clashes at the Donetsk airport between Ukrainian troops and the pro-Russian rebels, during his funeral in the village of Grabari on the outskirts of Donetsk May 29, 2014. Zverev, 43, was killed in the airport fighting when an operation by government aircraft strafed the airport and paratroops landed to reclaim it. REUTERS/Maxim Zmeyev (UKRAINE - Tags: POLITICS CIVIL UNREST OBITUARY) 

Relatives mourn near the coffin of Mark Zverev, a taxi driver shot dead on May 26, 2014 during clashes at the Donetsk airport between Ukrainian troops and the pro-Russian rebels, during his funeral in the village of Grabari on the outskirts of Donetsk May 29, 2014. Zverev, 43, was killed in the airport fighting when an operation by government aircraft strafed the airport and paratroops landed to reclaim it. REUTERS/Maxim Zmeyev (UKRAINE - Tags: POLITICS CIVIL UNREST OBITUARY) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A medic looks at thirty coffins prepared for the funerals of pro-Russian rebels killed during heavy fighting at Donetsk airport on May 26, outside a Donetsk morgue May 29, 2014. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. Medics look at thirty coffins prepared for the funerals of pro-Russian rebels killed during heavy fighting at Donetsk airport on May 26, outside a Donetsk morgue May 29, 2014. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A supporter of the self-proclaimed Donetsk People's Republic checks the area by a newly erected barricade on the airport road in the eastern Ukrainian city of Donetsk, May 28, 2014. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A supporter of the self-proclaimed Donetsk People's Republic sits behind a newly erected barricade on the airport road in the eastern Ukrainian city of Donetsk, May 28, 2014. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

Supporters of the self-proclaimed Donetsk People's Republic carry tyres as they erect a barricade on a road which leads to an airport in the eastern Ukrainian city of Donetsk, May 28, 2014. REUTERS/Maxim Zmeyev (UKRAINE - Tags: POLITICS CIVIL UNREST) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. 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. More than 50 pro-Russian rebels were killed in an unprecedented assault by Ukrainian government forces, which raged into a second day on Tuesday after a newly-elected president vowed to crush the revolt in the east once and for all. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A bloodstained icon of Jesus is seen among blood soaked shattered glass atop a wrecked truck near the Donetsk airport May 27, 2014. The truck used to ferry their fighters was wrecked on the airport road, covered in blood and completely riddled with bullets. More than 50 pro-Russian rebels were killed in an unprecedented assault by Ukrainian government forces, which raged into a second day on Tuesday after a newly-elected president vowed to crush the revolt in the east once and for all. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT TPX IMAGES OF THE DAY) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. Blood stains are seen on a wrecked rebel truck in a Donetsk neighborhood May 27, 2014. Two trucks ferrying rebels were attacked and destroyed during heavy fighting around the airport Tuesday morning. More than 50 pro-Russian rebels were killed in an unprecedented assault by Ukrainian government forces, which raged into a second day on Tuesday after a newly-elected president vowed to crush the revolt in the east once and for all. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. 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. More than 50 pro-Russian rebels were killed in an unprecedented assault by Ukrainian government forces, which raged into a second day on Tuesday after a newly-elected president vowed to crush the revolt in the east once and for all. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. Locals walk by a wrecked rebel truck in a Donetsk neighborhood May 27, 2014. Two trucks ferrying rebels were attacked and destroyed during heavy fighting around the airport on Tuesday morning. More than 50 pro-Russian rebels were killed in an unprecedented assault by Ukrainian government forces, which raged into a second day on Tuesday after a newly-elected president vowed to crush the revolt in the east once and for all. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. Locals stand by a wrecked truck near the Donetsk airport May 27, 2014. The truck used to ferry rebels was wrecked on the airport road, covered in blood and completely riddled with bullets. More than 50 pro-Russian rebels were killed in an unprecedented assault by Ukrainian government forces, which raged into a second day on Tuesday after a newly-elected president vowed to crush the revolt in the east once and for all. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A pool of blood is seen on the tarmac next to a wrecked military truck near the Donetsk airport May 27, 2014. Ukrainian forces fought with separatists in the city of Donetsk for a second day on Tuesday after inflicting heavy losses on the rebels while the government vowed to press on with a military offensive "until not a single terrorist" was left. A Kamaz truck of the type rebels use to ferry their fighters was wrecked on the airport road, covered in blood and completely riddled with bullet holes. Blood had spattered across the entire roadway and even reached a billboard seven metres above. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A local man stands by a wrecked Kamaz truck near the Donetsk airport May 27, 2014. Ukrainian forces fought with separatists in the city of Donetsk for a second day on Tuesday after inflicting heavy losses on the rebels while the government vowed to press on with a military offensive "until not a single terrorist" was left. The Kamaz truck of the type rebels use to ferry their fighters was wrecked on the airport road, covered in blood and completely riddled with bullet holes. Blood had spattered across the entire roadway and even reached a billboard seven metres above. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A Ukrainian helicopter Mi-24 gunship fires its cannons against rebels at the main terminal building of Donetsk international airport May 26, 2014.Three Ukrainian helicopter gunships mounted a heavy attack on the rebel-held international airport terminal at Donetsk on Monday, firing rockets and cannon and throwing out decoy flares as militants shot at them from the ground. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT MILITARY TRANSPORT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A Ukrainian helicopter Mi-24 gunship fires its cannons against rebels at the main terminal building of Donetsk international airport May 26, 2014. Three Ukrainian helicopter gunships mounted a heavy attack on the rebel-held international airport terminal at Donetsk on Monday, firing rockets and cannon and throwing out decoy flares as militants shot at them from the ground. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT MILITARY TRANSPORT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A Ukrainian helicopter Mi-24 gunship fires decoy flares over a residential area moments after attacking Donetsk international airport May 26, 2014. Three Ukrainian helicopter gunships mounted a heavy attack on the rebel-held international airport terminal at Donetsk on Monday, firing rockets and cannon and throwing out decoy flares as militants shot at them from the ground. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT MILITARY TRANSPORT TPX IMAGES OF THE DAY) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. 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 journalists near Donetsk international airport in eastern Ukraine heard gunfire and explosions in the vicinity and saw smoke billowing from inside the perimeter as fighter jets flew high overhead on Monday. On the day after a presidential election, gunmen forced the closure of the airport to flights and took over the terminal, demanding the withdrawal of Ukrainian forces from the facility. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT TPX IMAGES OF THE DAY) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A man, who could not reach the airport, looks at a military truck with armed pro-Russian militants passing through a police checkpoint towards the airport of the eastern Ukrainian city of Donetsk May 26, 2014. Armed pro-Russian separatists forced a shutdown on Monday of Donetsk airport in eastern Ukraine, an airport representative said, a day after they prevented a majority of the region's voters from taking part in presidential elections. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. 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. Armed pro-Russian separatists forced the closure of Donetsk airport, an airport representative said on Monday, a day after they prevented a majority of the region's voters from taking part in presidential elections. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. Smoke billows from Donetsk international airport during heavy fighting between Ukrainian and pro-Russian forces May 26, 2014. Three Ukrainian helicopter gunships mounted a heavy attack on the rebel-held international airport terminal at Donetsk on Monday, firing rockets and cannon and throwing out decoy flares as militants shot at them from the ground. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT TRANSPORT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. Smoke billows behind the main terminal of Donetsk international airport during heavy fighting between Ukrainian and pro-Russian forces May 26, 2014. Three Ukrainian helicopter gunships mounted a heavy attack on the rebel-held international airport terminal at Donetsk on Monday, firing rockets and cannon and throwing out decoy flares as militants shot at them from the ground. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT TRANSPORT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. Passengers and their suitcases are seen at a blocked junction close to the airport at the eastern Ukrainian city of Donetsk May 26, 2014. Armed pro-Russian separatists forced the closure of Donetsk airport, an airport representative said on Monday, a day after they prevented a majority of the region's voters from taking part in presidential elections. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. The air traffic control tower of Donetsk international airport is seen in the eastern Ukrainian city of Donetsk May 26, 2014. Armed pro-Russian separatists forced the closure of Donetsk airport, an airport representative said on Monday, a day after they prevented a majority of the region's voters from taking part in presidential elections. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. The terminal of Donetsk international airport is seen at the eastern Ukrainian city of Donetsk May 26, 2014. Armed pro-Russian separatists forced a shutdown on Monday of Donetsk airport in eastern Ukraine, an airport representative said, a day after they prevented a majority of the region's voters from taking part in presidential elections. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A rebel takes cover in a building near Donetsk international airport during heavy fighting May 26, 2014. Ukrainian government warplanes carried out airstrikes against pro-Russian rebels who seized Donetsk international airport on Monday, triggering a battle in and around the complex in a show of force by both sides after the election of a new president. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT MILITARY TRANSPORT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A family takes shelter in a building near Donetsk international airport during heavy fighting May 26, 2014. Ukrainian government warplanes carried out airstrikes against pro-Russian rebels who seized Donetsk international airport on Monday, triggering a battle in and around the complex in a show of force by both sides after the election of a new president. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT TRANSPORT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A local and a news photographer run for cover near Donetsk international airport during heavy fighting May 26, 2014. Ukrainian government warplanes carried out airstrikes against pro-Russian rebels who seized Donetsk international airport on Monday, triggering a battle in and around the complex in a show of force by both sides after the election of a new president. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT TRANSPORT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. People run for cover near Donetsk international airport during heavy fighting May 26, 2014. Ukrainian government warplanes carried out airstrikes against pro-Russian rebels who seized Donetsk international airport on Monday, triggering a battle in and around the complex in a show of force by both sides after the election of a new president. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A Ukrainian helicopter Mi-24 gunship fires its cannons against rebels at the main terminal building of Donetsk international airport May 26, 2014. Three Ukrainian helicopter gunships mounted a heavy attack on the rebel-held international airport terminal at Donetsk on Monday, firing rockets and cannon and throwing out decoy flares as militants shot at them from the ground. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT MILITARY TRANSPORT) 

EDITORIAL USE ONLY - NO COMMERCIAL OR BOOK SALES. A Ukrainian helicopter Mi-24 gunship flies over a residential area after attacking Donetsk international airport May 26, 2014. Three Ukrainian helicopter gunships mounted a heavy attack on the rebel-held international airport terminal at Donetsk on Monday, firing rockets and cannon and throwing out decoy flares as militants shot at them from the ground. REUTERS/Yannis Behrakis (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT MILITARY TRANSPORT)