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.

The drone blew out a wall and surrounding windows in the building in Sumy, a major city, just after 1 a.m., the Sumy regional administration said.

Russian first-person view (FPV) drones that use fiber optic cables instead of radio waves to connect with their controllers, making them impervious to jamming and other forms of electronic warfare. The Magyar Birds Brigade claims it has devised a system using mobile radars to provide early warning for incoming FPV drones several kilometers away.