When Russian paramilitary chief Yevgeny Prigozhin sent his Wagner mercenaries charging toward Moscow last year in a short-lived rebellion, President Vladimir Putin looked weak and vulnerable.

But just one year on from the most serious challenge to his authority in almost a quarter of a century in power, the Kremlin leader now appears more secure than ever.

Prigozhin was killed in an airplane crash two months after the mutiny, in which his Wagner fighters seized Russia's army headquarters in the southern city of Rostov-on-Don, shot down military aircraft and marched halfway to the capital before Belarus mediated a deal to end the 24-hour uprising.