Russian forces likely control the eastern Ukrainian town Soledar, in the Donetsk region, having advanced for the past four days, according to the British defence ministry.

Capturing Soledar, a daily update by the ministry said, is “likely an effort to envelop Bakhmut”, the highly contested city 10km (6 miles) from Soledar, where both sides have suffered heavy losses.

The defence ministry added: “Part of the fighting has focused on entrances to the 200km-long [124-mile] disused salt mine tunnels

which run underneath the district. Both sides are likely concerned that they could be used for infiltration behind their lines”.

Russia’s Wagner Group of mercenary fighters has attempted to capture Bakhmut and Soledar for months, despite the heavy loss of life.

According to Ukrainian journalist Yuriy Butusov, in Soledar, Russian forces have established fire control over the main Ukrainian supply route to the town.

Seizing Bakhmut would allow Moscow’s troops to advance to two more prominent cities, Kramatorsk and Sloviansk.