Russia attacked Ukraine's energy system and some cities with cruise and ballistic missiles plus drones on Wednesday in an "inhuman" Christmas Day assault, Ukraine's President Volodymyr Zelenskyy said.

Nearly three years into the war, the strikes wounded at least six people in the northeastern city of Kharkiv and killed one in the region of Dnipropetrovsk, the governors there said.

U.S. President Joe Biden denounced the "outrageous" attack and said he had asked the U.S. Defense Department to push forward with a new surge of military aid to Kyiv.