Ukrainian President Volodymyr Zelenskyy warned allies that the defense of his nation is a litmus test for broader Western resolve.

Russia launched a new barrage of missiles and drones at Ukraine on Wednesday, targeting gas infrastructure and other energy facilities in western regions in the latest strike on the country's hobbled power system as it approaches mid-winter.

Air defences were engaged in Ukraine's capital of Kyiv on Thursday to repel a Russian drone attack, officials said, and Reuters witness reported explosions in the city while British Prime Minister Keir Starmer was visiting.