A Ukrainian drone attack last week forced a refinery in Ryazan, southeast of Moscow, to suspend operations. Russia's Defense Ministry said in a statement on Friday that 49 Ukrainian drones had been downed over the country overnight, including 25 in the southern Rostov region and eight in the Volgograd region.

Officials say a Russian drone has blasted a hole in an apartment building in northeastern Ukraine during a nighttime attack that killed at least six people and wounded nine others.

A Russian drone struck a multi-storey apartment building in the northeastern Ukrainian city of Sumy early on Thursday, killing nine people and injuring 13, including a child, President Volodymyr Zelenskiy said.