Three years after a deadly explosion on a BP-leased drilling rig unleashed the worst environmental disaster in US history, the British energy giant is fighting to avoid billions in fines. BP's lawyers are trying to convince a federal judge that the 2010 Gulf of Mexico oil spill was not a result of gross negligence and to shift some blame -- and cost -- to its subcontractors at a blockbuster trial in New Orleans.

British energy giant BP on Friday said it would return up to $8.0 billion (6.2 billion euros) to company shareholders by repurchasing shares, a day after completing the sale of its stake in a Russian joint-venture. "BP announced today that it intends to carry out a share repurchase, or buy-back, programme with a total value of up to $8 billion," the group said in a statement. It added: "Today's decision to buy back shares follows the completion yesterday of the sale of BP's 50 percent interest in TNK-BP to Rosneft.

Russia's state oil giant Rosneft on Wednesday completed a $56-billion acquisition of the British and Russian stakes in the TNK-BP joint venture. "Congratulations on the completion of this deal," President Vladimir Putin told Rosneft chief Igor Sechin at a special ceremony at the Kremlin chief's suburban Moscow residence. "In my opinion, this was a very successful deal," news agencies quoted Putin as saying. The takeover's terms allow BP to acquire up to 20 percent of Rosneft's shares and give the British group an additional $17 billion in cash.

By Dmitry Zhdannikov LONDON (Reuters) - BP's oil trading division, the alma mater for a generation of the world's top traders and a former cash-generating machine, is under greater scrutiny after becoming a weak link for the oil major. The company says the unit, which once generated a tenth of profits, was responsible for its failure to fully deliver on a pledge to improve performance at its refining division.