Four people were killed and more than 50 injured in Ukraine after Russia pummeled targets across the country with drones and missiles for a second straight night.

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.

Following one of the most intense Russian air attacks since the start of the war more than three years ago, Ukrainian President Volodymyr Zelensky has called for increased international pressure on Moscow.