Kyiv mayor Vitali Klitschko says a Russian missile and drone attack on the capitla early Friday has killed at least four people and injured 20 others.

Russia launched drones and ballistic missiles at multiple targets across Ukraine, Kyiv authorities said on Friday, in a deadly air assault that left at least four people dead and 20 wounded in the capital.

Operation of the city's metro transport system was disrupted because a Russian strike had hit and damaged a train between stations. The air attack also triggered fires in residential buildings.