乌克兰顿涅茨克机场发生激战
There have been more fierce clashes in eastern Ukraine, where pro-Russian separatists are trying to capture Donetsk airport.
乌克兰东部地区发生激烈的武装冲突，亲俄派分离分子试图占领顿涅茨克机场。
Heavy firing could be heard near the airport - strategically important for both sides in the conflict.
A government spokesman said the rebels had broken into one of the terminals but were later pushed back. The rebels say they have seized the airport.
A truce agreed in eastern Ukraine on 5 September looks increasingly fragile.
On Friday US Secretary of State John Kerry spoke on the phone with his Russian counterpart Sergei Lavrov to "express his concern about intensifying violence in eastern Ukraine".
"Russia must use its influence with the separatists and end these attacks immediately", state department spokeswoman Jen Psaki said.
'Russian drones'
"The situation in the area of Donetsk airport remains difficult," Ukrainian military spokesman Vladyslav Seleznyov told Ukraine's Kanal 5 TV.
"The militants, using smoke bombs as a cover, broke into the ground floor of the old terminal," he said.
Ukrainian soldiers had pushed the rebels from half the building, Mr Seleznyov added.
But leaders of the self-proclaimed Donetsk People's Republic claimed that their fighters had seized the whole airport.
Eyewitnesses earlier told local media that a number of rebels had been killed during the clashes.
A correspondent for Associated Press news agency reported seeing three rebel tanks firing at the main terminal, with sniper shots ringing out.