By Andrew Osborn

LONDON Russia's most senior generals have dropped out of public view following a failed mercenary mutiny aimed at toppling the top brass, amid a drive by President Vladimir Putin to reassert his authority and unconfirmed reports of at least one arrest.

Valery Gerasimov, Russia's top general, has not appeared in public or on state TV since the aborted mutiny on Saturday when mercenary chief Yevgeny Prigozhin demanded Gerasimov be handed over. He has not been mentioned in a defence ministry press release since June 9 either.

Gerasimov, 67, is the commander of Russia's war in Ukraine, and the holder of one of Russia's three "nuclear briefcases," according to some Western military analysts.

Absent from view too is General Sergei Surovikin, nicknamed "General Armageddon" by the Russian press for his aggressive tactics in the Syrian conflict, who is deputy commander of Russian forces in Ukraine.

A New York Times report, based on a U.S. intelligence briefing, said on Tuesday he had advance knowledge of the mutiny and that Russian authorities were checking if he was complicit.

The Kremlin on Wednesday played down the report, saying that there was and would be a lot of speculation and gossip.

The Russian-language version of the Moscow Times and a military blogger reported Surovikin's arrest, while some other military correspondents who command large followings in Russia said he and other senior officers were being questioned about their possible role in the mutiny.

Reuters could not determine whether Surovikin had been arrested.

Rybar, an influential channel on the Telegram messaging application run by a former Russian defence ministry press officer, said a purge was underway.

He said the authorities were trying to weed out military personnel deemed to have shown "a lack of decisiveness" in putting down the mutiny amid some reports that parts of the armed forces appear to have done little to stop Wagner fighters in the initial stage of the rebellion.

"The armed insurgency by the Wagner private military company has become a pretext for a massive purge in the ranks of the Russian Armed Forces," said Rybar.

Such a move, if confirmed, could alter the way Russia wages its war in Ukraine — which it calls a "special military operation" — and cause turmoil in the ranks at a time when Moscow is trying to stymie a Ukrainian counteroffensive.

It could also cement or elevate the positions of other senior military and security figures regarded as loyal.

There was no official comment on what was going on from the defence ministry.

WINNERS AND LOSERS

Some Russian and Western military and political analysts believe Defence Minister Sergei Shoigu, a veteran Putin ally who Prigozhin wanted to bring down with Gerasimov because of his alleged incompetence, may actually now be safer in his job.

"I think he (Prigozhin) actually expected something would be done about Shoigu and Gerasimov, that Putin would rule in his favour," Michael Kofman, a Russian military specialist at the Carnegie Endowment think tank, wrote on Twitter.

"Instead, his mutiny may have ensured their continued tenure, despite being universally recognised as incompetent, and widely detested in the Russian Federation's armed forces."

Viktor Zolotov, head of the National Guard who used to be Putin's bodyguard, appears to be another beneficiary after appearing in public to say his men were ready to "stand to the death" to defend Moscow from Wagner.

He has spoken of the possibility of getting heavy weaponry and tanks for his forces in the wake of the mutiny.

Gerasimov was conspicuous by his absence when Putin on Tuesday thanked the army for averting a civil war, unlike Shoigu who has made several public appearances since.

Surovikin, Gerasimov's deputy, was last seen on Saturday when he appeared in a video appealing to Prigozhin to halt his mutiny. He looked exhausted and it was unclear if he was speaking under duress.

There were unconfirmed Russian media and blogger reports on Wednesday evening that Surovikin was being held in Moscow's Lefortovo detention facility after being arrested.

Alexei Venediktov, a well-connected journalist, said - without citing his sources - that Surovikin had not been in touch with his family since Saturday and that his bodyguards had gone silent too.

Prigozhin, who had spent months vilifying Shoigu and Gerasimov for their alleged incompetence in the Ukraine war, had frequently praised Surovikin who is widely respected in the army for his experience in Chechnya and Syria.

Surovikin, who did a stint as overall commander of the Ukraine war before Gerasimov was appointed to take over, is regarded by Western military analysts and by parts of the Ukrainian military as an effective operator.

He had been spoken of by Russian war correspondents as a potential future defence minister.

(Reporting by Andrew Osborn; Editing by Mike Collett-White and Lisa Shumaker)