The 31-year-old man suffered broken bones and bruises after struggling with unidentified assailants in a shopping area late on April 14.
The Interfax news agency reported that witnesses alleged the attackers may have been drunken police officers.
No confirmation was available.
It was not immediately clear if the incident was racially motiviated.
According to the nongovernmental organization Sova, two people have been killed and 14 injured in racially motivated attacks in St Petersburg this year.
(Interfax, AFP)