London, Jan 5 (IANS): The race to overthrow Vladimir Putin and grab his crown is underway, said Russian war analyst and former loyalist Igor Strelkov, according to a media report.

"The fight for the political Olympus has begun between the groupings that surround Putin," Strelkov said, Daily Mail reported.

Strelkov -- a former FSB colonel key to Putin's annexation of Crimea and subjugation of the Donetsk region of Ukraine in 2014 -- is now a staunch critic of the Kremlin's war strategy.

An immediate mass mobilisation of half a million more men is the only way for Putin to avoid defeat and ignominy in the war in Ukraine, he claimed, Daily Mail reported.

He spoke amid claims that Putin has approved in principle a huge new mobilisation drive.

The fight at the top of the Kremlin focuses on insurgent Putin crony Yevgeny Prigozhin, head of the Wagner private army, and loyalist forces in the defence ministry around weakening defence minister Sergei Shoigu, according to Strelkov, Daily Mail reported.

Others believe security apparatchiks around ex-FSB head Nikolai Patrushev -- secretary of the powerful security council -- are more likely to pull the trigger on Putin in a bid to save the elite ruling circle if the war continues to go wrong.

Some claim the security bloc is lining up his son and Agriculture Minister Dmitry Patrushev as the frontman for a coup replacing Putin if he is forced out by war setbacks or ill health, Daily Mail reported.

Strelkov sees Prigozhin, once Putin's 'chef' in charge of Kremlin banquets, as aiming to be a major political force in his own right, and there is evidence he is now securing prominent coverage in the state media.

There has been speculation he wants to become Defence Minister - or even President, Daily Mail reported.