The assault of Lev Ponomaryov, 67, leader of the organization For Human Rights, follows similar attacks on opposition figures in Moscow, RIA Novosti reported Wednesday.
The incident late Tuesday occurred after he had stepped out of his car and a stranger asked him to light a cigarette. Ponomaryov said someone else struck him in the head. He said he was knocked to the ground and kicked and beaten by two or three men until a doorman rescued him.
"It was an ordered attack," he was quoted as saying. "It's connected with my human rights activities. I've been involved in a few sensitive issues lately."
Ponomaryov, a Soviet-era dissident, was elected to parliament in the early 1990s. The news service said he worked to expose abuses in the Russian prison system, and he helped establish the Solidarity democratic opposition movement last year.
Recently, he has criticized the government's prosecution of Mikhail Khodorkovsky, the jailed oil tycoon
and Kremlin critic. He is being tried on embezzlement and money laundering charges.