By Alexei Anishchuk
NOVO-OGARYOVO, Russia (Reuters) - Vladimir Putin could free a former oil tycoon and members of the Pussy Riot band, all portrayed as political prisoners by domestic and foreign critics, under an amnesty expected by the end of the year, according to a Kremlin human rights adviser.
Mikhail Khodorkovsky, who supporters say was jailed to curb a political challenge to Putin, putting his oil assets in state hands, and two Pussy Riot inmates are due for release next year. But an early discharge could help improve Putin's image before he hosts the Sochi 2014 Winter Olympics in February.
Putin told his presidential human rights council in September to make suggestions for an amnesty to mark the 20th anniversary of Russia's post-Soviet constitution in December.
After meeting Putin, rights council head Mikhail Fedotov told reporters he believed Khodorkovsky and two jailed Pussy Riot members, Nadezhda Tolokonnikova and Maria Alyokhina, would be eligible for release under the amnesty.
"I think so," Fedotov told reporters after the meeting. "Those are non-violent crimes."
Putin has repeatedly denied anyone in Russia has been jailed for political reasons.
Former Yukos oil company chief Khodorkovsky has been in jail since his arrest in 2003 and was convicted of financial crimes in two trials. In the eyes of Kremlin critics at home and abroad, his jailing is one of the main black marks on the record of Putin, who has not ruled out seeking another six-year term as president in 2018.
THIRD TERM CLAMPDOWN
Tolokonnikova and Alyokhina are due for release in March after serving two-year sentences for an impromptu "punk prayer" protest against Putin in Russia's main cathedral in February 2012, infuriating the Russian Orthodox Church and offending many believers. Khodorkovsky is due for release in August.
Putin's spokesman, Dmitry Peskov, said it was too early to name who might come under an amnesty.
"To speak of this now is hasty and not correct," he told reporters at Putin's residence at Novo-Ogaryovo outside Moscow. "Clear criteria will be determined ... in dialogue with experts and civil society."
Putin's opponents are watching for signs of conciliatory gestures after what they say has been a clampdown on dissent and curtailment of freedoms since he won a third term last year despite the biggest opposition protests of his 13-year rule.
Putin left his intentions unclear.
"This amnesty can only apply to individuals who did not commit grave crimes or crimes involving violence against representatives of the authorities, by this I mean law enforcement officers," he told Fedotov and Russian human rights ombudsman Vladimir Lukin.
"I agree with you that such actions should underscore the humanism of our state, but they certainly must not ... give anyone the impression they can commit a crime today and count on forgiveness from the state tomorrow," Putin said.
Putin did not specify what he meant by grave crimes.
Legally, the term can apply to a broad array of crimes including those Khodorkovsky and Pussy Riot were convicted of. Fedotov later told TV and Internet channel Dozhd the council's proposal would release many held for nonviolent crimes.
Putin's reference to law enforcement officers was seen as an instruction that the amnesty should not apply to 12 people on trial and others facing charges over violence that erupted at protests on the eve of his inauguration in May 2012.
(Reporting by Alexei Anishchuk; Editing by Steve Gutterman and Ralph Boulton)