Officials in Kyiv have said Moscow stepped up a powerful assault on Soledar in the industrial Donbas region, forcing Ukrainian troops to repel waves of attacks led by the Wagner contract militia around the salt mining town and nearby fronts.

Soledar is a few miles from Bakhmut, where troops of both sides have suffered heavy losses in some of the most intense trench warfare since Russia invaded Ukraine nearly 11 months ago.

"Russia's Soledar axis is highly likely an effort to envelop Bakhmut from the north, and to disrupt Ukrainian lines of communication," Britain added in its intelligence update.

(Reporting by Kanjyik Ghosh in Bengaluru; Editing by Clarence Fernandez)