Officials in Kyiv say Russian forces have been stockpiling drones and missiles for systematic attacks on Ukraine's struggling energy grid over winter months.

“A total of 48 Shahed-136/131 strike UAVs were launched,” the Ukrainian air force said in a statement, adding that defensive systems had downed 41 of the unmanned aerial vehicles.

Russian strikes on Ukraine's energy infrastructure last winter left millions in the cold and dark for extended periods.

Kyiv has bolstered its air defense systems since with Western arms, but conceded that it needs more weapons to protect vulnerable regions.