Kyiv. The head of the Russian private army Wagner says his force lost more than 20,000 fighters in the drawn-out battle for Bakhmut, with about 20% of the 50,000 Russian convicts he recruited to fight in the 15-month war dying in the eastern Ukrainian city.

The figure was in stark contrast with claims from Moscow that it lost just over 6,000 troops in the war, and is higher than the official estimate of the Soviet losses in the Afghanistan war of 15,000 troops between 1979-89. Ukraine hasn't said how many of its soldiers have died since Russia's full-scale invasion in February 2022.

Analysts believe the nine-month fight for Bakhmut alone has cost the lives of tens of thousands of soldiers, among them convicts who reportedly received little training before being sent to the front.

Russia’s invasion goal of “demilitarizing” Ukraine has backfired because Kyiv’s military has become stronger with the supply of weapons and training by its Western allies, Wagner chief Yevgeny Prigozhin said in an interview published late Tuesday with Konstantin Dolgov, a pro-Kremlin political strategist.

Prigozhin also said the Kremlin’s forces have killed civilians during the war, something Moscow has repeatedly and vehemently denied.

Prigozhin, a wealthy businessman with longtime links to Russian President Vladimir Putin, is known for his bluster -- often spiced with obscenities -- and has previously made unverifiable claims, some of which he later backtracked on.

Earlier this month, his spokespeople published a video of him shouting, swearing and pointing at about 30 uniformed bodies lying on the ground, saying they were Wagner fighters who died in a single day. He claimed the Russian Defense Ministry had starved his men of ammunition and threatened to give up the fight for Bakhmut.

He also said in Tuesday's interview it was possible that Kyiv’s anticipated counteroffensive in coming weeks, given continued Western support, might push Russian forces out of southern and eastern Ukraine as well as annexed Crimea.

“A pessimistic scenario: the Ukrainians are given missiles, they prepare troops, of course they will continue their offensive, try to counterattack," he said. "They will attack Crimea, they will try to blow up the Crimean bridge (to the Russian mainland), cut off (our) supply lines. Therefore, we need to prepare for a hard war.”

The Ukrainian General Staff said Wednesday that “heavy fighting” is continuing inside Bakhmut, days after Russia said that it completely captured the devastated city.

Bakhmut lies in Donetsk province, one of four provinces Russia illegally annexed last fall and only partially controls.

The head of Ukraine’s ground forces, Oleksandr Syrskyi, said that Kyiv’s forces “are continuing their defensive operation” in Bakhmut, and have attained unspecified “successes” on the city’s outskirts. He gave no further details.

Ukrainian officials have insisted the battle for Bakhmut isn’t over.

A Ukrainian commander in Bakhmut told The Associated Press on Tuesday that the Ukrainians have a plan to push the Russians out of all occupied territory.

“But now we don’t need to fight in Bakhmut, we need to surround it from flanks and block it,” Yevhen Mezhevikin said. "Then we should ‘sweep’ it. This is more appropriate, and that’s what we are doing now.”