Russian President Vladimir Putin’s whereabouts remain unknown following the short-lived rebellion from the Wagner mercenary group.
There has been speculation that the Russian leader fled Moscow during the crisis after his presidential jets were tracked leaving the city.
The US Secretary of State Antony Blinken said the events show the cracks in Mr Putin's authority.
Yevgeny Prigozhin, the head of the Wagner mercenary group, has left Russia for Belarus after abandoning his advance on Moscow.