Clashes broke out between two groups at Hazaribagh in Jharkhand when a right-wing group's procession to mark the demolition of the Babri Masjid was passing through the town on Thursday.
The people in the "Shaurya Diwas" procession burnt six motorcycles and damaged several cars parked on the street, the police said. When the police tried to intervene, the mob started throwing stones at policemen.
Videos taken by eyewitnesses show people throwing stones at buildings and the police at the town 95 km from state capital Ranchi.
The police said they have banned any large gathering in the area to prevent a flare-up. The district commissioner and a senior police officer came to the area to directly control the situation.
Over 12 people have been detained. The Rapid Action Force has also been deployed.