Ukraine’s defence ministry says its troops have withdrawn from the main terminal of Donetsk airport, the scene of bitter fighting in recent weeks.
It said the military retained control of parts of the airport, but that six soldiers had died and 16 were wounded.
In Donetsk itself, at least nine people were killed when a civilian bus was hit by shelling.
Fighting between the army and Russian-backed separatists has intensified in and around rebel-held Donetsk.
The deaths come after Ukraine, Russia, France and Germany issued a joint call to end fighting in the east.
They also agreed on a line of demarcation between separatists and government forces from which both sides are meant to withdraw their forces, but so far this has not been carried out.
The airport just outside Donetsk, which is no longer in use, has taken on symbolic value for both separatists and the government.
Ukraine’s defence ministry said 20 Ukrainian soldiers had withdrawn from the main terminal because their positions were destroyed and they were under direct shelling.
The loss of the main terminal is a major blow to pro-Kiev forces and will send political shockwaves back to the capital, the BBC’s David Stern reports from Kiev.
The defence ministry blamed separatists for the shelling of the bus, saying their own forces were 15km (9 miles) away.
But Russian Foreign Minister Sergei Lavrov said Ukrainian forces were to blame for what he called a “monstrous new crime” and a “coarse provocation”.