Russia claimed Sunday that its forces are for the first time pushing into the central Ukrainian region of Dnipropetrovsk, an area it has been trying to reach for months, in a move that could create new problems for Kyiv’s much-stretched forces.

Russia struck Ukraine with a thunderous aerial bombardment overnight, further dampening hopes that the warring sides could reach a peace deal anytime soon.

Air assaults on Saturday killed at least four people. Kharkiv’s mayor described an overnight strike as “the most powerful attack” since the beginning of the war.