Putin foes who, like Prigozhin, have suffered mysterious fates

Yevgeny Prigozhin, 62, spearheaded a mutiny against Russia's top army brass on June 23-24, which President Vladimir Putin said could have tipped Russia into civil war.

Others who have opposed Putin or his interests have also died under unclear circumstances or come close to death.

Here are some details about these mysterious incidents...

Alexei Navalny 

Russia's most prominent opposition leader, Alexei Navalny, was flown to Germany in August 2020 for medical treatment after being poisoned in Siberia with what Western experts concluded was the military nerve agent Novichok. Russia has denied any involvement.

Navalny earned admiration around the world for voluntarily returning to Russia in 2021. He was immediately arrested on arrival. He is now serving sentences totalling 11-1/2 years on fraud and other charges that he says are bogus. His political movement has been outlawed and declared "extremist". Navalny had an extra 19 years in a maximum security penal colony added to his jail term recently.

Sergei Skripal

A former Russian double agent who passed secrets to British intelligence, Sergei Skripal and his daughter Yulia were found unconscious on a bench outside a shopping centre in the English cathedral city of Salisbury in March 2018.

They were taken to hospital in critical condition, and British officials said they had been poisoned with Novichok, a group of nerve agents developed by the Soviet military in the 1970s and 1980s. Both survived.