Ukraine on Thursday accused Russia of deliberately targeting civilians after 30 people were killed when two buses were blown up in the frontline city of Kramatorsk, in one of the deadliest single attacks for weeks.

Photos posted by local authorities showed the burnt-out metal shell of the vehicles, with the blurred-out images of bodies and debris strewn across the road.

Police said the buses were hit with a glide bomb.

The strikes come just a day after five children were among 22 killed when a Russian missile struck a five-storey apartment block in Pryluky, in the northern Chernigiv region.

"The Russians are deliberately targeting civilians," Donetsk Governor Vadym Filashkin said, accusing Moscow of flouting "every conceivable rule of warfare and norm of international humanitarian law".

Kramatorsk City Council called it "yet another horrific crime committed by the Russian army against the civilia...