Khamroev told RFE/RL's Uzbek Service today that the incident took place on January 14.
"I was entering the Tula metro station at about 11 pm and talking to my brother [over my mobile phone] when suddenly three men in their late 20s started beating me up without any reason," he said. "One of them was a bearded, Russian-looking guy. I lost consciousness. After I recovered I went to the police at the metro station and they launched an investigation."
Khamroev says the assaulters knocked him to the ground and kicked him repeatedly in the head, the face, and the back.
A member of Uzbekistan's Birlik oppposition movement, Khamroev left his home country in 1992. He reportedly obtained Russian citizenship three years later.
Khamroev works with Civic Assistance (Grazhdanskoye Sodeistviye), a Moscow-headquartered nongovernmental organization that helps asylum seekers from Central Asia and elsewhere.
(RFE/RL's Uzbek Service, uznews.net)