MOSCOW, Sep 07, 2011 (Dow Jones) -- Russian Federal Anti-Monopoly Service, or FAS, has commenced a lawsuit against the world's biggest aluminum producer United Co. Rusal PLC (0486.HK), suspecting the company of abusing its dominant position on the local market.

FAS has started the lawsuit against a Rusal trading subsidiary, which it suspects of enforcing disadvantageous conditions of supply to a counterparty.

Rusal spokeswoman called the FAS's claims "groundless."