Igor I Sechin, chief executive of Rosneft and confidant of the Russian president, Vladimir V Putin, is the most powerful oilman you?ve never heard of. And Sechin, a former military spy who is awkward in front of cameras, long preferred it that way. But he might not be able to remain in the shadows for much longer. In recent months, Sechin has struck a series of bold deals with Western oil companies to develop Siberia and Russia?s Arctic waters, and he is on the prowl for more.

The man nicknamed ?The Scariest Man on Earth? because of his espionage background is now at economic conferences and visiting boardrooms in New York and Berlin as he seeks to build up Rosneft, the Russian state oil company.

On Tuesday, Rosneft announced that it had begun negotiations on what would be its biggest deal ever: to buy the British oil giant BP?s share of its Russian joint venture. BP estimates that its stake in the venture, TNK-BP, is worth about $30 billion.

The deal, if consummated, would help Putin and Sechin consolidate their control over Russia?s valuable energy assets, the linchpin of the nation?s economy, at a time when the Russian industry is facing stiff challenges to finding new sources of oil to replace aging fields. It would also cement Rosneft?s position as the biggest publicly traded oil company in the world as Putin begins his third presidential term.

Rosneft already claims the largest proven oil reserves of a listed company, though other, nonpublic state companies such as Saudi Aramco have far more. The company?s production of 2.4 million barrels per day now surpasses BP?s output of 2.3 million, including its portion from TNK-BP, and Exxon Mobil?s level of 2.2 million. If Rosneft acquires BP?s stake in TNK-BP, its daily output would rise to 3.3 million barrels per day ? more than the country of Iraq and well ahead of other public companies.

?Rosneft believes that an acquisition of BP?s interest in TNK-BP would be in the best interest of both Rosneft?s and BP?s shareholders and would lead to further development of TNK-BP,? Rosneft said in a statement. Rosneft said it approached BP only after BP had announced interest from another potential buyer in June. For its part, BP said it ?welcomed today?s announcement by Rosneft of its interest in commencing negotiations?.

BP is also negotiating a possible sale to its Russian partners, a group of Soviet-born billionaires that include Len Blavatnik, who lives in New York, and two Russian-based partners. But BP will be hard pressed to turn down the state company?s bid, in no small part because of the presence of Sechin, who was deputy prime minister until May.

Sechin declined to be interviewed. But his recent actions seem to signal a desire on the part of the Kremlin to work with Western companies to more fully develop Russia?s oil and gas resources while also ensuring that the government retains control over the assets.

For BP, the Russian joint venture has provided a gusher of cash, generating $19 billion over nearly a decade. But BP and its Russian partners have clashed repeatedly over whether and how to expand. And last year, the Russian partners, including the oligarch Mikhail Fridman, successfully blocked a separate deal that BP had struck with Rosneft to explore Russia?s Arctic waters. That maneuver embarrassed Putin, who had publicly championed the BP-Rosneft alliance.

BP, oil analysts say, wants to sell its TNK-BP stake in part as a means to divorce from its partners and make a new alliance with Sechin, who is said to be an opponent of Fridman.

Any sale of BP?s stake in TNK-BP is at least three months away, the period that BP must, under its shareholder agreement, negotiate on the buyout offer from its current partners. Further muddying any possible deal are allegations of fraud from a former TNK-BP employee against the company?s management, which emerged Tuesday in a London court.

The former director of logistics accused one of the Russian shareholders, German Khan, who is also a manager, of funneling hundreds of millions of dollars in bribes to Russian officials in the guise of subcontracts. TNK-BP lawyers denied the allegation as wholly unsubstantiated, Bloomberg News reported.