Former German Chancellor Gerhard Schroeder and mining industry veteran James Leng quit the board of BP's Russian joint venture TNK-BP on Friday, two sources close to the company said.

TNK-BP is beset by a conflict between its shareholders. The two independent board members left after a meeting of the board on Friday, the sources added.

BP's local partners -- a quartet of Soviet-born billionaires grouped into the Alfa-Access-Renova (AAR) consortium -- took the British major to arbitration over its failed attempt to enter an alliance with TNK-BP rival Rosneft .

AAR said the attempted deal violated their shareholders' agreement.

On Friday, the board had been due to discuss the option of suing either BP or AAR for breaches of the shareholders' agreement, sources said before the meeting. Major litigation must be approved by the board of the 50-50 joint venture.

Schroeder and Leng, former chairman of Rio Tinto , had been serving as independent directors on the TNK-BP board together with Russian industry lobbyist and former senior government official Alexander Shokhin.

(Reporting by Melissa Akin and Douglas Busvine; Editing by David Hulmes)