A State Duma (Russian congress) member and his aide attacked police officers with clubs in downtown Moscow early Tuesday, the police said.

Vladislav Dyomin, a member of the Liberal Democratic Party of Russia, his aide Alexei Kozertsky and an unidentified man stopped a patrol car near the Ulitsa 1905 Goda metro station at about 5 a.m. Tuesday, a police official said. The men were intoxicated, she said.

When two police officers got out of the vehicle, Dyomin screamed, "Beat the cops!" and punched one of them in the face with his fist, the official said. Kozertsky pulled some clubs from a sport-utility vehicle parked nearby, and the men began to beat the policemen with them. The attack was broken up when another patrol car pulled up a few minutes later.

Dyomin, 29, produced his Duma documents -- which give him immunity from prosecution -- and walked away free, the police said. Kozertsky was detained, while the third attacker fled. The policemen suffered bruising to their faces.

LDPR officials were unavailable for comment Tuesday.