Nearly half a million households were left without power on Christmas Day in frigid weather after further missile attacks by Russia on Ukraine's damaged power grid, according to multiple reports.

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 Zelenskiy said.

The Christmas Day attack was the thirteenth time this year Russia has targeted Ukraine's energy infrastructure.