The governor of Luhansk in eastern Ukraine says Ukrainian forces have attacked the base of the Russian private military company Wagner Group in the region.

Serhiy Haidai wrote on social media on Monday that the base was located in Popasna, currently occupied by Russia.

He said Ukrainian forces "successfully struck the enemy's headquarters," and that the number of those killed is being clarified.

Analysis by Britain's Defence Ministry has indicated Russia was using Wagner operatives to reinforce its frontline forces. It said the group almost certainly played a central role in recent fighting in the region.

Wagner is also believed to have carried out an attack in July on a facility in the eastern region of Donetsk, where Ukrainian soldiers were being held as prisoners. More than 50 people are thought to have died. Ukraine and western countries have condemned Moscow for the incident, saying it will be held accountable.