A law enforcement official said that Palamumi Saushiwa, a graduate student at a St. Petersburg medical school, has been diagnosed with a brain concussion, and that an inquiry into the apparently racially motivated attack was underway.
The incident came just five days after a similar attack in St. Petersburg on an Afghan national, which left him with a severe brain injury.
St. Petersburg and other major Russian cities have experienced a wave of xenophobic attacks in recent months. Most such attacks target dark-skinned foreigners and migrants from Central Asia and the Caucasus.
According to the Sova rights center, at least 40 people fell victim to apparently racially motivated murders in Russia last year, and more than 300 were injured in hate attacks.