A mentally troubled young man ransacked an old mosque in downtown Kolkata on Tuesday, sparking a brief demonstration by local people.

Police intervened in time to remove a roadblock put up by local youths after the young man entered the Tipu Sultan mosque in the Esplanade area, broke open a cupboard and damaged some books.

The incident occurred in the afternoon when the chief cleric of the mosque and other caretakers were resting.

The man, whom police later described as "mad", was prevented from causing more damage by local people who overpowered him and handed him over to the police.

Immediately after the incident, tension spread in the area. But things were brought under control by the timely intervention of police and mosque officials, who convinced the angry youths to let traffic move on the arterial Lenin Street.

Chief Minister Buddhadeb Bhattacharya was informed about the incident. Members of the West Bengal Minorities Commission will meet Bhattacharya on Wednesday on the issue.

Police have also called a meeting of local community leaders on Wednesday to encourage interaction with them.