Mayor of Ukraine's Kharkiv says bombing of city has increased significantly

Four civilian residents of Ukraine's eastern second city Kharkiv were killed and ten were wounded on Wednesday as Russian forces stepped up their bombing campaign of the city, local officials said.

"The enemy is bombing residential homes, residential areas. Unfortunately, there are civilian casualties - the worst thing is that children are dying," Kharkiv mayor Ihor Terekhov told Ukrainian national television.

Kharkiv region Governor Oleh Synehubov later wrote on the Telegram messaging app that four people were killed and ten wounded by strikes on the city on Wednesday.

Kharkiv has already come under significant Russian strikes, with Terekhov saying there hadn't been a single day without strikes since the start of the invasion on Feb. 24.