U.K. oil major BP PLC (BP) has accused one of its Russian billionaire partners in the TNK-BP joint venture of violating a shareholder agreement, filing a notice of arbitration in Stockholm, the shareholder said Tuesday.

The move to fire back at its partners in the TNK-BP joint venture comes after BP's attempt to form a strategic alliance with Russian state oil company OAO Rosneft (ROSN.RS) collapsed in May, following a legal victory by its partners in TNK-BP Ltd. (TNBP.RS)

A spokesman for Soviet-born business tycoon Viktor Vekselberg, who holds a 12.5% stake in the TNK-BP oil joint venture through his Renova Holding, said BP filed the arbitration notice on Friday, alleging that Renova violated the shareholder agreement between BP and Alfa-Access-Renova, the consortium of billionaires who jointly control TNK-BP with the U.K. energy giant.

The billionaire partners, also known as AAR, claimed that the Rosneft tie-up would violate the TNK-BP shareholder agreement that requires BP and AAR to offer TNK-BP any energy proposals in Russia before working with others.

In turn, BP now alleges that Vekselberg has breached the shareholder agreement by holding large natural gas and fuel assets through his IES Holding Ltd., Russia's largest private power supply company.

The Renova spokesman maintained that the holding company hasn't violated the terms of the TNK-BP shareholder agreement.

BP Tuesday declined to confirm or deny whether a notice of arbitration had been filed, only saying that "arbitration is a confidential matter."

Last month, AAR recommenced legal proceedings against BP in an attempt to win billions of dollars in compensation from the U.K. oil company for the alleged damage done to the joint venture.

Also last month, a Russian court ordered BP and TNK-BP to provide documents in preparation for a lawsuit by minority shareholders in TNK-BP, who say that BP caused losses of up to several billion dollars by preventing TNK-BP from replacing BP in the Rosneft deal earlier this year.

-By Jacob Gronholt-Pedersen and Alexis Flynn, Dow Jones Newswires; +7 495 232 9197; jacob.pedersen@dowjones.com

(William Mauldin in Moscow contributed to this story.)