MOSCOW (AP) - Exiled tycoon and former prisoner Mikhail Khodorkovsky, in a rare public appearance Wednesday, threw down the gauntlet to the Kremlin, saying revolution in Russia in inevitable and that he will help to bring it about.

MOSCOW (AP) Exiled tycoon and former prisoner Mikhail Khodorkovsky, in a rare public appearance Wednesday, threw down the gauntlet to the Kremlin, saying revolution in Russia in inevitable and that he will help to bring it about.

Speaking on Wednesday at a conference in London, Khodorkovsky accused the Kremlin of pursuing a suicidal foreign policy, introducing unlawful laws and prosecuting citizens with the use of corrupt courts developments that he described as an "anti-constitutional coup."

He said President Vladimir Putin has driven Russia into a position when a revolution is "inevitable and necessary."

The 10 years that Khodorkovsky served in a Russian prison transformed an oligarch into a symbol of anti-government resistance.

Once Russia's richest man, the charges of tax evasion and embezzlement against Khodorkovsky have been seen as punishment for challenging the Kremlin and harboring political ambitions. Upon his release, he left the country and has remained in exile.

The 52-year old said he is not interested in politics as a career but he "cannot stand idle and watch what is going on in Russia" and would like to help a peaceful revolution.

"I will certainly do my best to ensure that the rule of law is restored through a revolution, so that as a result ... Putin and his entourage will have to be held accountable to society in front of an independent court," Khodorkovsky said.

Khodorkovsky had spent 10 years in prison on two sets of charges when he was pardoned and released in December 2013, shortly before the Winter Games in Sochi. He had been due to be released in August the following year.

Khodorkovsky said on Wednesday that when he was pardoned he gave his word to Putin not to go into politics before his prison term would have ended and while he was taking care of his ailing mother. Since his mother died last August, Khodorkovsky said he felt he "no longer had any obligations."

In an unexpected raising of tensions, Russian investigators this week called Khodorkovsky for questioning in connection with a murder investigation, in a summons delivered to his elderly father's home in Moscow in connection.

Investigators announced in June that they were reopening the probe into the 1998 slaying of Vladimir Petukhov, mayor of Nefteyugansk, the town where Khodorkovsky's company, Yukos, was headquartered at the time. Khodorkovsky and his associates have denied involvement in the killing.

Khodorkovsky said on Wednesday that he had no intention of working with Russian investigators, whom he accused of concocting the charges. A former security chief at Yukos was sentenced to life in prison in 2007 for ordering the murder.