Russia's Wagner group has taken full control of the eastern part of the Ukrainian city of Bakhmut, its founder Yevgeny Prigozhin said on Wednesday.
Reuters could not independently confirm the report which, if true, would mean Russian forces control close to half of the city.
"Units of the private military company Wagner have taken control of the eastern part of Bakhmut," Prigozhin said in a voice recording on the Telegram messaging platform of his press service.
"Everything east of the Bakhmutka River is completely under the control of Wagner," he said.
The report is as yet unverified
Reuters was not able to independently verify the report. Last Friday, Prigozhin said his forces had the city "practically surrounded," though the mercenary boss has appeared to issue premature claims of territorial gains in the past.
Prigozhin's forces have led the assault on the city but he has clashed repeatedly with Russia's defense ministry, complaining that his men have been starved of the ammunition they need.
In a separate video posted on his Telegram channel later on Wednesday, standing in front of a tank with explosions raging in the background, Prigozhin called on Ukrainian President Volodymyr Zelensky to "take the old people and children" out of the battered city.
Russian forces have been trying to seize Bakhmut for months in what has become possibly the bloodiest battle of the year-long war.
If Russian forces do capture the city it will become their first significant territorial gain since last summer.
Russian Defence Minister Sergei Shoigu said on Tuesday the seizure of Bakhmut would seriously weaken Ukraine's defenses and allow Russia to mount further offensives across the Donbas - the eastern Ukrainian regions of Donetsk and Luhansk which Russia says it is fighting to "liberate."
US Defence Secretary Lloyd Austin downplayed the strategic importance of the city on Monday, saying its capture would represent only a symbolic victory and would not turn the tide of the war.
Zelenskiy has said Ukraine will continue fighting for Bakhmut amid talk of a possible Ukrainian withdrawal. Prigozhin said on Tuesday he saw no signs Ukraine was pulling its forces out of the city.