Ukraine says it has destroyed nine Russian helicopters in an air strike on two cities in the Russian-occupied east of the country.
A special forces statement said an air defence system and other equipment were hit, as well as a munitions dump, in the cities of Berdyansk and Luhansk.
Dozens of Russian troops were killed or injured in the operation, it added.
There has been no independent confirmation of the attack, and no comment from the Russian military.
Vladimir Rogov, the Russian-appointed governor of the occupied part of Zaporizhzhia region, said air defence systems “successfully intercepted enemy rockets” over Berdyansk, adding that information about casualties and damage was being checked and would be provided later.
But an unverified video on a pro-Russian social media account – said to have been filmed in Berdyansk – appears to show explosions and flying rockets, while a voice explains that an ammunition dump has been hit.
Another Russian blogger has written of an attack on an airfield with US-made ATACMS rockets, inflicting what the author described as a “serious blow”, with losses of people and technology.
The Ukrainian military said the attack on Berdyansk happened at 04:00 local time (01:00 GMT) and on Luhansk at 11:00 local time.
Berdyansk is approximately 85km (53 miles) from the nearest front line while Luhansk is almost 100km away.
Clashes have continued to be reported along the front line, including around the Ukrainian-held towns of Avdiivka, Kupyansk and Lyman, which have been coming under heavy bombardment from Russian forces in recent days.
- Russia attacks east Ukraine stronghold of Avdiivka
Ukraine’s emergency services say a dormitory building has been destroyed in a Russian attack on the eastern city of Slovyansk, with two people believed to be trapped under the rubble.
In Odesa, the authorities say debris from Russian drones that were shot down has damaged a yacht club and several yachts, but caused no casualties.
Ukraine has been trying to take back territory occupied by Russia in the east and south of the country through a major counter-offensive, but has so far made slow progress.
It has also made frequent air attacks on Russian positions as it aims to undermine Moscow’s war effort.
Russia has also been attacking Ukrainian positions in the east around Avdiivka and Kupyansk, but according to Ukrainian reports has suffered heavy casualties in recent days.
