Kyiv, though, said its troops were still resisting.
On Thursday (January 12) Ukraine's border guard released this footage of what it said was fighting in Soledar.
Reuters could not verify the date or the location of the footage, or the situation on the ground in the town, where the Russian assault has been relentless.
Moscow's defense ministry announced the capture, and said it was made possible by constant bombardment from the air, by missiles and artillery on the part of Russian forces.
These Ukrainian tanks are operating near the city of Bakhmut, close to Soledar.
The defense ministry said seizing Soledar would help Russia cut off Ukrainian supply routes to Bakhmut, and trap remaining Ukrainian forces there.
Moscow has been trying to seize Bakhmut for months.
It made no mention of the Russian mercenary group Wagner, which said earlier this week it had seized Soledar.
But Serhiy Cherevatyi, spokesperson for Ukraine's eastern military command, told Reuters by telephone on Friday, quote, "our units are there, the town is not under Russian control."
Kyiv and the West have played down the small salt-mining town's significance.
Saying Moscow sacrificed wave upon wave of soldiers and mercenaries in a pointless fight for a bombed-out wasteland, that is unlikely to affect the wider war apart from sapping manpower.
But capturing Soledar would be a trophy for Moscow, and it has taken on outsized importance.
