Russia targeted Ukrainian energy facilities and struck civilian infrastructure in overnight attacks, Ukrainian officials said on Thursday, and a U.N. monitoring body said Moscow's strikes on the power grid probably violated humanitarian law.

A partial evacuation has been ordered in Russia's Tver region after a "massive" Ukrainian drone attack sparked a fire there, the local governor has said. Igor Rudenya said emergencies services in the town of Toropets were trying to "localise" the blaze caused by falling drone wreckage.