Memorial, the human rights group, said Wednesday that one of its activists was attacked by an unidentified man, possibly a police officer, after responding to a call for help in southwestern Moscow, Interfax reported.
The activist, Bakhrom Khamroyev, arrived at an apartment building on Profsoyuznaya Ulitsa after a Central Asia-born Russian resident called him to say armed men had come to his home, the report said.
A man in regular clothes exited a minivan parked near the apartment building and struck Khamroyev on the head several times.
Khamroyev refused hospitalization but suffered a concussion that prevented him from going to the police to file a complaint Wednesday, Memorial head Oleg Orlov said. He added that the attacker was likely a law enforcement officer, but did not elaborate.
The attack was criticized by Amnesty International, and the presidential rights council promised to track an investigation into the incident.