MOSCOW - In a surprise decision, President Vladimir Putin announced Thursday that jailed former oil tycoon Mikhail Khodorkovsky will be pardoned, a move that will see his top foe and Russia's onetime richest man freed after more than a decade in prison.

The development, along with an amnesty for two jailed members of the Pussy Riot punk band and the 30-member crew of a Greenpeace protest ship, appeared aimed at easing international criticism of Russia's human-rights record ahead of February's Winter Olympics in Sochi, Putin's pet project.

Putin waited until just after his tightly choreographed annual news conference to make the announcement, dropping the biggest news of the day after journalists had already peppered him with questions in a four-hour marathon.

Putin said the 50-year-old Khodorkovsky, who was set to be released next August, had submitted an appeal for pardon, something he had refused to do before.

"He has spent more than 10 years behind bars. It's a tough punishment," Putin said. "He's citing humanitarian aspects - his mother is ill. A decree to pardon him will be signed shortly."

The head of the Kremlin's United Russia faction said he expects Khodorkovsky to celebrate the New Year at home with his family.

Khodorkovsky's son, Pavel, tweeted: "Very happy news. Waiting to speak with my father to learn more."

Putin's announcement "came as a big surprise for me, totally out of the blue," Khodorkovsky's mother, Maria, told RT television.

"We are old people, and we are waiting, hoping to live to the moment when we can embrace him," his father, Boris, said in remarks posted on the Slon.ru online newspaper.

Analysts viewed the decision as a clever step ahead of the Sochi Olympics.

"At first blush, the pardon for Khodorkovsky appears to be a rather canny move that will throw Putin's critics off-balance in the run-up to Sochi, while sending a clear message of self-confidence to his domestic political opponents," Andrew Weiss of the Carnegie Endowment for International Peace said in a written commentary.

In October 2003, masked commandos stormed into Khodorkovsky's jet on the tarmac of a Siberian airport and arrested him at gunpoint. He was found guilty of tax evasion in 2005 and convicted of embezzlement in a second case in 2010.

Critics have dismissed the charges against Khodorkovsky as a Kremlin vendetta for challenging Putin's power. During Putin's first term as president, the oil tycoon angered the Kremlin by funding opposition parties and also was believed to harbor personal political ambitions.

His actions defied an unwritten pact between Putin and a narrow circle of billionaire tycoons, dubbed "oligarchs," under which the government refrained from reviewing privatization deals that made them enormously rich in the years after the Soviet collapse on condition that they didn't meddle in politics.