MOSCOW - Russia said on Friday it had launched a massive attack on Ukraine using land, sea and air-launched missiles and drones, part of what it said was a series of "revenge strikes" to punish Kyiv for attacking Russian border regions.

The defence ministry said in a statement its forces had successfully struck a number of power grid objects, railway nodes, military factories, ammunition depots and concentrations of Ukrainian troops and foreign mercenaries.

"As a result of the strike, the work of industrial enterprises producing and repairing weapons, military equipment and ammunition was disrupted," it said.

"In addition, foreign military equipment and lethal weaponry delivered to Ukraine from NATO countries was destroyed, the transfer of enemy reserves to the front line was disrupted, and Ukrainian army units and mercenaries were hit."

Reuters could not independently verify the detailed claims on the extent of damage. Kyiv said Russia's strike had been its largest on Ukrainian energy infrastructure of the war, hitting a vast dam, killing at least five people and leaving more than a million others without electricity.

The Russian defence ministry said the attack was one of a series of 49 revenge strikes launched since March 16 in response to Ukrainian shelling of Russian territory and attempts by Ukraine-backed forces to break through the border and seize Russian border settlements.

That was a reference to Russia's Belgorod region which has come under increasingly heavy Ukrainian fire and where Russian forces have clashed with Kyiv-backed armed groups which have tried to storm and seize small Russian settlements.

"As a result of the strikes, the Ukrainian army's decision-making centres, airfield infrastructure facilities, repair shops for weapons and military equipment, storage depots for drones and uncrewed boats, logistics bases, and temporary deployment points for special operations forces and foreign mercenaries have been hit," the Russian defence ministry said.

  - Reuters