MOSCOW, Sept 16 - The board of Russia's No.2 mobile phone group Vimpelcom backed a bid for Ukrainian firm RadioSystem (URS) but failed to diffuse the risk of a protracted legal battle, the company said on Friday.

"...management plans to finalize the negotiations for the acquisition of URS unless someone challenges us in court," Vimpelcom Chief Executive Alexander Izosimov said in a statement, Rueters reported.