Former oil mogul Mikhail Khodorkovsky said on Sunday he would not seek power in Russia but fight for the freedom of political prisoners, challenging Vladimir Putin two days after the president freed him from jail, according to Reuters. After more than a decade in prison that made him a symbol of what Putin's critics say is his intolerance of dissent, Khodorkovsky, 50, told reporters in Berlin that "the struggle for power is not for me". But he made clear he would put pressure on Putin and urged world leaders and "we who are free" to do the same. "We need to work further so that there would be no more political prisoners left in Russia and other countries," he told a news conference at a museum near the site of the Berlin Wall. "I am going to do my utmost in this regard." As reported, Putin unexpectedly announced on Thursday he would pardon Khodorkovsky, jailed in 2003 on fraud and tax evasion charges but seen by many as a political prisoner. Khodorkovsky said there were no conditions attached to his release and he had made no admission of guilt in asking Putin for a pardon. Once Russia's richest man, the former oil baron said he was financially secure and would not go back into business. Many observers said the pardon was part of a drive by Putin, who could seek another six-year term in 2018, to improve his image before Russia hosts the Olympics in Sochi in February.