At least two people have been killed and another 17 injured in the biggest Russian drone attack on Ukraine's second-largest city of Kharkiv, the mayor says. Ihor Terekhov says that overnight Russia launched 48 drones, as well as two missiles and four gliding bombs.

A stunning attack in Russia highlights how small drones can be outfitted with new software and components to turn them into killing machines.

The barrage included 407 drones and 44 ballistic and cruise missiles, Ukrainian air force spokesperson Yurii Ihnat said.