A crowd of 20 to 25 people attacked a team of police officers Saturday as they were arresting a man who allegedly sexually assaulted a 15-year-old girl.
RIA Novosti said one of the officers was hit with brass knuckles and suffered serious head injuries.
In response to the attack, Moscow police launched raids of city markets to check workers for complicity in criminal activity.
Authorities said they have detained more than 470 people as part of the checks.
The alleged attacker who injured the officer Saturday, Magomed Rasulov, was also arrested Monday while trying to flee the city on a bus, RIA Novosti said.