Eastern Ukrainian town renowned for its salt mines has been the centre of days of fierce fighting.

The head of Russia’s mercenary Wagner Group has claimed to have secured control of the salt mining town of Soledar in Ukraine’s east, but uncertainty remains amid continued battles in the city centre.

Soledar has been the focus of days of intense fighting as Russia has viewed it as key to its campaign for the nearby strategic city of Bakhmut and Ukraine’s larger eastern Donbas region.

It was not possible to verify the conditions on the ground, and Ukrainian officials have not commented on the situation.

“Wagner units took control of the entire territory of Soledar. A cauldron has been formed in the centre of the city in which urban fighting is going on,” Russian news agencies reported Wagner head Yevgeny Prigozhin, a close ally of Russian President Vladimir Putin, as saying late on Tuesday.

“The number of prisoners will be announced tomorrow,” Prigozhin added. The encircled Ukrainian soldiers had been given an ultimatum to surrender by midnight (22:00 GMT), the group said on Telegram.

Soledar is about 15km (9 miles) from Bakhmut, and its capture would have symbolic, military and commercial value for Russia.

The Russian state RIA news agency later issued a report saying that Wagner Group had taken over Soledar’s salt mines following “fierce fighting”, while Prigozhin shared a photo of himself surrounded by his mercenaries in what he said was one of the mines.

Still, the Institute for the Study of War, a Washington, DC-based think tank, expressed caution about the Russian claims.

“Russian forces have not captured the entirety of #Soledar despite false Russian claims that the city has fallen and that #Bakhmut risks imminent encirclement,” it said in a Twitter thread, noting that Prigozhin himself had acknowledged urban warfare was continuing.

Heavy cost

Ukrainian President Volodymyr Zelenskyy did not mention control of Soledar in his regular video address on Tuesday evening when he repeated his call for more Western weapons, saying Russia was looking to intensify its military campaign. He did not provide details.

But Ukraine’s Defence Ministry tweeted late on Tuesday, “Even after suffering colossal losses, Russia is still maniacally trying to seize Soledar — home to the largest salt mine in Europe.”

Ukraine said earlier its forces were still holding onto positions in Soledar, withstanding assaults by wave after wave of Russian forces seeking their first battlefield victory in months.

Seizing Soledar would be Russia’s most substantial gain since August, after a series of humiliating retreats in the northeast and south in the second half of 2022.

But any victory in Bakhmut would come at an enormous cost, with troops from both sides having taken heavy losses in some of the most intense fighting since Russia invaded Ukraine on February 24 last year.

Kyiv has released pictures in recent days showing what it says are many Russian soldiers strewn dead in muddy fields.

Moscow says capturing Bakhmut would be a crucial step towards taking full control of Ukraine’s Donetsk region, one of four provinces it claimed to have annexed two months ago.