MOSCOW, Russia — President Vladimir Putin announced yesterday that he would pardon ex-oil tycoon and bitter Kremlin critic Mikhail Khodorkovy, a move that should see Russia’s most famous prisoner freed after more than a decade behind bars.

The shock announcement could finally draw the curtain on the most notorious legal case in post-Soviet Russian history and came as Russia comes under even greater international scrutiny in the run-up to the Winter Olympic Games in February.

Khodorkovsky’s imprisonment on embezzlement and fraud convictions in jails including a Siberian penal colony has dented Russia’s investment climate and become a symbol of the erosion of human rights under Putin.

Putin revealed after his marathon annual news conference that Khodorkovsky, 50, had for the first time written a request for a pardon, citing humanitarian circumstances as his mother is ill.

Khodorkovsky’s legal team and even his mother said they did not know if the former oil tycoon, who has been in prison since 2003, had asked for a pardon, but Putin’s spokesman told AFP the request had been personally signed by him.

He had been due to be released in August 2014 and is currently serving out his term at a penal colony in the remote town of Segezha in the northwestern Karelia region.

Khodorkovsky’s mother Marina, who last saw her son in August, said she was unaware of the request and the difficulty of communicating with inmates means that she will only be able to phone him at the weekend.

Prisoners “are allowed to make phone calls once a week, on Saturdays. So, I can’t learn about his response before Saturday,” she told RT television.

The pardon coincides with an amnesty for some prisoners in Russia that is also expected to include the jailed female punks from anti-Kremlin rock group Pussy Riot.

Khodorkovsky has repeatedly indicated that he would not ask Putin for a pardon because that would be tantamount to admitting his guilt.

He occasionally joked bitterly that he would remain in jail indefinitely.

“It is hard for me to imagine the possibility of being released: 10 years in prison is not a joke,” he told opposition weekly The New Times for which he wrote a column about his life in prison.

Putin has denied that Khodorkovsky’s jail term was politically motivated but his statements have repeatedly betrayed a visceral animosity for the tycoon.

Just before Khodorkovsky was sentenced to a second term in prison in 2010, Putin said on television that “a thief must be in prison.”

Khodorkovsky for his part frequently needled the Russian leader with his jabs from prison, saying famously that Putin loved only dogs.