BP Plc (BP/) is in talks to buy a direct stake in an East Siberian oil producer from OAO Rosneft, the Russian oil producer facing U.S. and European financing bans, according to a person with direct knowledge of the matter. The talks about Rosneft’s Tass Yuriakh unit started some time ago, according to the person, who asked not to be identified because the information isn’t public. The stake may be valued at $700 million to $800 million, according to Russian daily Kommersant, which reported the deal earlier today. BP has remained committed to its partnership with Rosneft, in which it holds 20 percent, as Russia ’s relations with the U.S. and Europe sour over the conflict in Ukraine. U.S.-led sanctions, which restrict Rosneft from borrowing internationally and limit access to offshore and shale technology, don’t stop it from selling assets. BP has been seeking direct production ventures in Russia […]