LONDON: Russia's Rosneft is to take a “pretty significant stake” in oil major BP Plc, Sky television news said Friday. “That is probably going to be around 5 percent, I understand, though the details were still be finalized today,” its reporter Mark Kleinman said. BP invited reporters to a press conference, to be addressed by Chief Executive Bob Dudley and scheduled for 2100 GMT Friday, at its headquarters in London. BP, Europe's third-largest listed oil company by market capitalization, earlier said Dudley was in Moscow on Friday for a “routine” meeting with Prime Minister Vladimir Putin. BP's CEO travels to Russia once every quarter for meetings with officials. Sky news television said the British oil major will announce an exchange of shares with Rosneft, while a source familiar with the matter said the planned deal would involve the two companies jointly exploring for oil and gas in Russia and other places. BP already owns a roughly 1 percent stake in Rosneft, and last year it struck a complex deal to effectively borrow against the stake when it was rushing to raise funds to help pay for the cost of the Gulf of Mexico oil spill. For BP, which already has a significant joint venture in Russian known as TNK-BP, such a deal might give it greater access to Russia's vast resources of oil and gas. For Rosneft, an agreement could be an opportunity to pick up BP's shares while they are still depressed in the aftermath of last year's Deepwater Horizon disaster in the Gulf of Mexico. Many analysts believe the company's shares remain undervalued as BP battles the massive cleanup and legal costs of the spill. A BP spokesman issued a statement saying: “Following recent press speculation, BP confirms it is in discussions with Rosneft relating to a possible arrangement. A further announcement is to be made later today.” A share swap deal could allow BP to drill for oil and gas in the untouched and totally unproven waters in the Russian part of the Arctic.