The leader of the Russian mercenary group Wagner announced that his forces had begun to withdraw from the Ukrainian town of Bakhmut.
Yevgeny Prigozhin has vowed to hand over control of the city to the Russian military by June 1, but kyiv says he still controls parts of the city.
He said his forces were ready to return if the Russian regular army proved unable to handle the situation.
The battle for the city was the longest and bloodiest of the war.
Wagner’s mercenaries led the fighting there for the Russian side, and Mr Prigozhin said this week that 20,000 of his fighters had died at Bakhmut.
“We are withdrawing units from Bakhmut today,” Prigozhin said in a video streamed on Telegram from the destroyed town.
BBC Verify geotagged the video to an area near a pharmacy east of Bakhmut.
Mr Prigozhin – who announced the capture of the town on Saturday – is seen telling his men to leave ammunition for the Russian army. He adds that some Wagner fighters will stay behind to help the Russian troops.
“When the soldiers are in a difficult situation, they will stand up,” he said, before warning two fighters not to “intimidate the soldiers”.
Wagner’s boss has repeatedly targeted senior Russian military officials, publicly criticizing them for not supporting his troops. Last month, he even threatened to withdraw his troops from the city if they did not receive much-needed ammunition.
Despite Wagner’s claims to deliver Bakhmut, Ukraine did not admit that the city had fallen.
Ukrainian Deputy Defense Minister Hanna Maliar said on Thursday that her forces still controlled part of the Litak district, southwest of the city.
“The enemy has replaced Wagner’s units in the suburbs with regular army troops. Inside the city proper, Wagner’s forces are still present,” she posted on Telegram.
Analysts say Bakhmut has little strategic value for Moscow, but his capture would be a symbolic victory for Russia after the longest battle in the war in Ukraine so far.
Wagner’s mercenaries had concentrated their efforts on the city for months, and their relentless and costly tactic of sending in waves of men seemed to have gradually eroded Kiev’s resistance.
Mr Prigozhin became a key player in the full-scale Russian invasion of Ukraine launched in February 2022, leading the private army of mercenaries.
He recruited thousands of convicted criminals to his group – no matter how serious their crimes – as long as they agreed to fight for Wagner in Ukraine.
About half of the 20,000 Wagner fighters who died at Bakhmut were convicts, Prigozhin said this week.
Earlier this month, the United States said it believed more than 20,000 Russian troops had been killed in the Battle of Bakhmut and another 80,000 injured. The BBC is unable to independently verify the figures.
Ukraine did not release figures on its casualties in Bakhmut, but also suffered heavy casualties.
Capturing Bakhmut would bring Russia one step closer to its goal of controlling the entire Donetsk region, one of four regions in eastern and southern Ukraine annexed by Russia last September as a result of referendums widely condemned outside Russia as a sham.
However, when Russia fought hard to claim the cities of Severodonetsk and Lysychansk last summer, Ukraine quickly clawed back swathes of territory elsewhere.
There were around 70,000 people living in Bakhmut before the invasion, but only a few thousand people remain in the devastated town, once known for its salt and gypsum mines and huge vineyard.