AKIPRESS.COM - Ukrainian troops and pro-Russian separatists on Wednesday fought their first serious battles in months and Ukraine's defense minister said an attempt by rebels to take the eastern town of Maryinka had been thwarted.

The Ukrainian military said the Russian-backed rebels had tried to advance using tanks and up to 1,000 fighters west of the main rebel stronghold of Donetsk, in the most significant escalation of the conflict in about three months and in defiance of a ceasefire deal, reports Reuters.

Estimates of casualties varied. The separatists, who denied their forces had launched an assault, said 15 people had been killed when government troops fired artillery into rebel-held territory near the city.

A Ukrainian presidential spokesman, Yuri Biryukov, on his Facebook page put total casualties at 7 p.m. (1600 gmt) at two dead and 30 injured, while regional police chief Vyacheslav Abroskin said three civilians had been killed.

In Moscow, the Kremlin immediately took the side of the separatists, accusing the Ukrainian armed forces of carrying out provocative actions.

"In Moscow, we are following very closely, and are deeply concerned by, the provocative actions by the Ukrainian armed forces that are, as far as we can see, provoking the situation," Kremlin spokesman Dmitry Peskov told journalists on a call.

Russian Foreign Minister Sergei Lavrov said those responsible for the fresh fighting were trying to halt progress in internationally-brokered peace talks.