Mikhail Khodorkovsky, the one-time Russian oil tycoon who was imprisoned for a decade, says on Sunday that he has no plans to return to business world but to do all he can to ensure the release of other political prisoners in Russia. "The time that is left for me, it could be used to do business, but I would like to devote it to the activity of paying back the debts to the people and by that I mean the people who are still in prison," he said. Speaking at a news conference in Berlin, Khodorkovsky also has thanked German chancellor Angela Merkel and former Foreign Minister Genscher for helping his release. He said the Russian government has assured him it would be safe to return to the country, he believes there is no guarantee that he would be allowed to leave again. He said he would focus on public activity, but not intend to get involved in politics or finance Russia’s political opposition. The now 50-year-old was convicted in 2003 for tax evasion and money-laundering. He was pardoned on Friday by Putin and immediately flew in a private jet to Berlin. There has been speculation over what remains of the vast fortune that once made him Russia’s richest man.