"In the Donbass (eastern Ukraine), this night was not a calm one. The enemy shelled positions of the 'anti-terrorist operation' forces with the same intensity as before," a statement by the military said, Reuters reported.

Fighting had been particularly intense around Debaltseve, a key railway junction linking the two main rebel areas, where separatists had used rockets and artillery to attack government forces holding the town, the statement said.

"Following military action and shelling ... Ukraine lost eight service personnel and 34 others were wounded," military spokesman Vladyslav Seleznyov said.