The total cost of Russian oil giant OAO Rosneft's (ROSN.RS) deal to buy 50% of TNK-BP Ltd. from the AAR consortium of tycoons will be $28 billion plus interest at 3.75% per annum from Oct. 16 to the closing date of the deal, Rosneft said in a statement Thursday, confirming its board had approved the deal.

State-controlled Rosneft and
AAR signed a definitive agreement Wednesday as part of a $55 billion deal that will make Rosneft the largest listed oil producer by output. Rosneft agreed a final deal to buy out BP PLC's (BP) 50% stake in TNK-BP in October. The deals are expected to close in the first half of next year.

In a statement Thursday, Rosneft also said its board had approved the company's memorandum of understanding with a subsidiary of Venezuela's state oil company Petroleos de Venezuela SA to develop heavy oil reserves in the South American country, as well as providing the company with a loan.

Rosneft will hold a 40% stake in the Carabobo-2 North and Carabobo-4 West blocks in the
Orinoco heavy oil belt, with the rest owned by PdVSA. Rosneft will pay an entry bonus of $1.1 billion and extend a market rate $1.5 billion credit facility to PdVSA.