A concentrated, nine-minute-long Russian drone attack on Ukraine's second largest city of Kharkiv in the middle of the night killed three people and injured 64, including nine children, Ukrainian officials said on Wednesday.

Russia attacked the frontline Ukrainian regions of Kharkiv and Kherson with artillery fire, guided bombs and drones, killing three people and injuring at least 68.

One of the hardest-hit areas was the city of Kharkiv in northeastern Ukraine, where 17 attack drones struck two residential districts, Mayor Ihor Terekhov said. Emergency crews, municipal workers and volunteers worked through the night to extinguish fires, rescue residents from burning homes, and restore gas, electricity and water services.