The whereabouts of Prigozhin have been subject to much speculation since his failed mutiny and apparent exile to Belarus in June.

There were claims last week he has had tea with Mr Putin and a video was shared appearing to show him with his forces in Belarus.

Now pictures have emerged that appear to show Prigozhin at a hotel being used for the Russia-Africa Summit event in the Russian city.

Are US and Russia in secret talks? - Ukraine war latest updates

One image was posted to a Facebook page that appears to be for Dimitri Sytyi, a reported associate of the Wagner Group that has been based in the Central African Republic.

Sky News has verified that the image was taken in the Trezzini Palace Hotel in St Petersburg.

Another image has been posted within Wagner-supporting channels. These posts also claim that he is in St Petersburg and meeting African leaders.

Sky News is working to identify the men pictured with Prigozhin.

Prigozhin - whose Wagner forces have been a key asset to Russia's successes on the frontline in Ukraine, including in the battle for Bakhmut - has repeatedly accused General Valery Gerasimov and Russia's defence minister Sergei Shoigu of botching the war.

During the aborted mutiny that saw his mercenary troops march on Moscow last month, Prigozhin described it not as a military coup but a "march for justice".

The fact he continues to be at liberty has raised questions about the strength of Mr Putin's position and whether a shadowy struggle for power has been playing out behind the walls of the Kremlin.

Also on Thursday, reports have emerged that Ukrainian forces have broken through Russian defences in southern Ukraine in what could be a significant moment in the war.