Heavily armed Russian mercenaries withdrew from the southern Russian city of Rostov overnight under a deal that defused an unprecedented challenge to the authority of President Vladimir Putin and halted their rapid advance on Moscow.

Fighters of the Wagner group returned to their bases in return for guarantees for their safety and the leader, Yevgeny Prigozhin, will move to Belarus, according to the agreement mediated by Belarusian President Alexander Lukashenko.

Prigozhin was seen leaving the district military headquarters in Rostov — hundreds of miles south of Moscow — late on Saturday in a sports utility vehicle. His whereabouts on Sunday were not immediately clear.

Videos shared on social media from Rostov overnight purportedly showed the mercenaries withdrawing from the city in a convoy of armoured vehicles, tanks and coaches to the sound of cheers, chants of “Wagner” and celebratory gunfire from residents.

“Take care of yourselves,” shouted one woman.

Moscow was calm on Sunday, with the Red Square closed but otherwise little evidence of increased security in the streets. Monday has been declared a non-working day to allow time for things to settle.

Chechen special forces who deployed to the Rostov region to resist the mercenaries’ advance were also withdrawing back to where they had been fighting in Ukraine, commander Apty Alaudinov said in a video published on Telegram.

Under the deal, brokered late on Saturday, Kremlin spokesman Dmitry Peskov said a criminal case opened against Prigozhin for armed mutiny would be dropped, Prigozhin would move to Belarus, and Wagner fighters who rallied to his cause would face no action, in recognition of their previous service to Russia.

In a televised address during Saturday’s drama, Putin said the rebellion put Russia’s very existence under threat.

Russian forces shelled the southern Ukrainian city of Kherson, killing one civilian man, the local governor said on Sunday.

Russia’s foreign ministry on Sunday said China had expressed support for Russia’s leadership in its efforts to stabilise the domestic situation. Russia’s deputy foreign minister Andrei Rudenko held a meeting with China’s foreign Minister Qin Gang after flying to Beijing for talks on “international” issues.