At least three children were among 27 people wounded as a result of a Russian drone attack on Ukraine's second-largest city of Kharkiv overnight that damaged apartments and a kindergarten, Ukrainian authorities said on Monday.

Russian drones attacked the Ukrainian city of Kharkiv early on Monday, according to Governor Oleh Syniehubov. Mayor Ihor Terekhov said at least 27 people were injured in the strikes.

Ukraine said it struck a Russian air base on Saturday, while Russia continued to attack Ukraine with hundreds of drones overnight as part of a stepped-up bombing campaign that has dashed hopes for a breakthrough in efforts to end the more than 3-year-old war.