Kyiv has said that Russia has again prepared a campaign to pummel the country's energy infrastructure as freezing temperatures have hit.

Officials in Kyiv said air defences had downed the missiles at about 4:00 am local time (0200 GMT) but falling debris over the Darnytskyi district injured four people.

"Medics provided them with help at the scene," said Kyiv mayor Vitali Klitschko on social media.

"Also, a missile fragment was found on the territory of a warehouse in Darnytskyi district. There was no fire or damage to the building."

The air force said that Russia had launched the drones from the Crimean peninsula that was annexed by Moscow in 2014.

During the winter of 2022, such strikes left millions of people without power for long periods during a cold snap.

Kyiv has since reinforced its air defence systems with weapons from its European and US allies, but says more is needed to protect vulnerable regions.