State oil major Rosneft has finalized a deal to buy 50 percent of Russian peer TNK-BP from the AAR consortium for $28 billion, sealing the country's largest takeover.

AAR and Rosneft said on Wednesday the deal should be completed in the first half of 2013 pending approvals from Russian and European regulators.

AAR chief executive Stan Polovets told Reuters the consortium, representing Len Blavatnik, Mikhail Fridman, German Khan and Viktor Vekselberg, will receive $28 billion cash. There had been reports the tycoons might get some Rosneft shares.

"I can confirm that it is $28 billion in cash at closing."

Rosneft is also acquiring the other half of TNP-BP, Russia's third-largest crude producer, from BP for cash and stock in a deal worth $27 billion which will make the British company a major shareholder in Rosneft.

Rosneft, headed by Igor Sechin - a close ally of President Vladimir Putin, is now confronted with the task of combining the operations of two major producers while also implementing a raft of exploration deals concluded earlier with BP rivals.

(Reporting by Vladimir Soldatkin; Editing by Douglas Busvine and Dan Lalor)