Documents uncovered in a Berlin archive revealed Matthias Warnig, 49, who played a leading role in the controversial forced sell-off of part of the Yukos oil giant, was once an agent of the East German secret police, the Stasi.

Yukos' Siberian unit was sold at rock-bottom prices

According to research by The Wall Street Journal, Warnig - now the head of the Russian division of Germany's Dresdner Bank - cooperated with Putin to recruit informers for the Soviets in Western countries when the Russian leader was serving in Dresden as a KGB colonel during the late 1980s.

Several former Stasi employees and acquaintances of the two men have confirmed their relationship. Dresdner has admitted that its employee was a spy but denied that he knew Putin in Germany, saying that they met later.

Among deals won by Dresdner Bank from the Russian government was the contract to evaluate Yuganskneftegas, the Siberian production unit of Yukos that was sold off at a rock-bottom price last December, ostensibly to recover billions of pounds of alleged back taxes.

Mikhail Khodorkovsky, the former chief executive of Yukos, is currently on trial for fraud and tax evasion in a prosecution that is widely seen as a political attack instigated by Putin.

While there is no suggestion contracts have been awarded inappropriately, opponents of the Russian president have called for an inquiry to establish whether Warnig or his company had benefited from his relationship with Putin.

``There now needs to be a full, objective investigation into the whole murky business surrounding the evaluation and sale of Yuganskneftegas,'' said Irina Khakamada, a democratic reformer who challenged Putin for the presidency last year.

Warnig has become an influential deal maker since he moved to Russia in the early 1990s and was recently nominated to become a board member of the state energy giant, Gazprom.

The investment banking arm of Dresdner Bank, DrKW, was awarded the contract to evaluate the prized Yuganskneftegas unit of Yukos without competition from other banks. Yukos claimed the division was worth 16 billion (HK$236 billion), but the bank recommended 8 billion - a figure regarded as fair by independent analysts - and the government later sold it for 5 billion.

Yukos remained suspicious of the bank and later launched legal action against DrKW, accusing it of raising financing to help the state gain control of Yuganskneftegas through a shell company. The action was dropped earlier this month when the bank was able to show it had not participated in the auction. A Yukos adviser said, however it was unsettled by the news of Warnig's relationship with Putin.

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