General Sergei Surovikin, the deputy commander of the Russian forces fighting in Ukraine, is believed to have been detained days after mercenaries staged a revolt in Russia, two people familiar with the matter told the Associated Press, citing US and Ukrainian intelligence assessments.

It is not clear whether Gen Surovikin faces any charges or where he is being held, reflecting the opaque world of the Kremlin’s politics and uncertainty after the revolt.

But his reported detention comes days after Wagner Group mercenaries took over the military headquarters in the Russian city of Rostov-on-Don and were heading towards Moscow in what appears to have been an aborted insurrection.

Wagner head Yevgeny Prigozhin has spoken positively of Gen Surovikin while criticising the country’s military brass and suggested that he should be appointed the general staff chief to replace General Valery Gerasimov.

The New York Times this week reported that US officials believe Gen Surovikin had advance knowledge of Mr Prigozhin’s plan to stage the revolt.

The White House and the Kremlin declined to comment.

Gen Surovikin, who has longtime links to Mr Prigozhin, has not been seen since the start of the rebellion when he posted a video urging an end to it.

A Russian military blogger, the Moscow Times, and the Financial Times reported that Gen Surovikin, who is also the commander of the Russian air force, has been arrested.

There has been intense speculation that some top military officers may have colluded with Mr Prigozhin and may now face punishment for the mutiny that briefly sent a virtually unchallenged march towards Moscow that President Vladimir Putin has labelled as treason and a “stab in the back”.

Alexei Venediktov, former head of the Ekho Moskvy, a prominent independent radio station that was shut down by authorities after Moscow invaded Ukraine, said Gen Surovikin and his close lieutenants have not been in contact with their families for three days, but stopped short of saying that he was detained.

Another prominent military messaging channel, Rybar, which is run by a former defence ministry press officer, reported a purge in the ranks was under way as authorities looked into allegations that some could have sided with Mr Prigozhin.

Gen Surovikin has been linked to Mr Prigozhin since both were active in Syria, where Russia has waged a military action since 2015 to shore up Syrian President Bashar Assad’s government and to help him reclaim territory after a devastating civil war.

While Mr Prigozhin had unleashed expletive-ridden insults at embattled defence minister Sergei Shoigu and Gen Gerasimov before last week’s mutiny in which he demanded their ousting, he has continually praised Gen Surovikin.

When the rebellion began, however, Gen Surovikin recorded a video urging a halt to the mutiny.

Earlier this week, the New York Times reported that US officials believed that Gen Surovikin had advance knowledge about the mutiny. Asked about that report, Kremlin spokesman Dmitry Peskov shrugged it off as part of “speculation and gossip”.

On Thursday, Mr Peskov refused to comment on whether Gen Surovikin had been arrested.

Asked by the Associated Press if the president still trusts Gen Surovikin, he replied that Mr Putin works with the defence minister and the chief of the general staff and referred questions about officers to the Defence Ministry. He also referred all other questions about Gen Surovikin and his status to the ministry.

Gen Surovikin, who was nicknamed “General Armageddon” by Western media for his brutal tactics in Syria and Ukraine, was credited with shoring up Russian defences after Moscow’s retreat from broad areas of Ukrainian territory last autumn amid a swift counter-offensive by Kyiv.

Named by Mr Putin in the autumn to lead Russian forces in Ukraine, Gen Surovikin presided over the bombing campaign that targeted Ukraine’s power plants and other vital infrastructure but failed to knock out power supplies.

In January, Mr Putin replaced him with Gen Gerasimov, putting the general staff chief in charge of the Russian battle in Ukraine. Gen Surovikin was demoted to the position of Gen Gerasimov’s deputy.

Gen Gerasimov’s own fate also is unclear after the abortive mutiny. While Mr Shoigu showed up at several events attended by Mr Putin, Gen Gerasimov was absent.

If a purge is indeed under way, it could destabilise the military chain of command and erode troop morale amid the early stage of Ukraine’s latest counter-offensive and offer Kyiv a chance to reclaim more ground.