DOW JONES NEWSWIRES BP PLC's (BP, BP.LN) joint venture in Russia, TNK-BP (TNBP.RS), lost a court battle with federal authorities over its claim of nearly $30 million in interest on overpaid customs duties, business daily Vedomosti reports Thursday. TNK-BP sued the Federal Customs Service in March, seeking to recover 921.6 million rubles ($29.6 million) in interest because the agency missed a deadline for reimbursing the oil company for its overpayment. On Wednesday, the Moscow Arbitration Court rejected TNK-BP's claim, a company spokesman said. TNK-BP will appeal the decision, he said. The interest is based on RUB3.9 billion in excess duties on oil exports the company paid for 2006 and 2007 due to an erroneous assessment by the customs service. Last year, TNK-BP got the money back after Russia's Supreme Arbitration Court ruled in a similar case that the agency's refusal to refund overpayments of duties was illegal. TNK-BP argued that Russian law requires overpayment reimbursements to be made within one month after a claim is filed, company lawyer Eduard Godzdanker said. TNK-BP is owed the interest that accrued during the nearly two years it took the customs service to return the money, he added. Newspaper website: www.vedomosti.ru -Dow Jones Newswires; 212-416-2900 (END) Dow Jones Newswires June 16, 2010 20:02 ET (00:02 GMT)