Five persons, including an additional superintendent of police, were killed and 25 injured as violence erupted near the North Bengal town of Coochbehar on Monday after which authorities clamped curfew.

The violence erupted when a 22,000-strong mob attacked the police contingent led by Additional SP (Kalimpong) Mustaq Ahmed, in their bid to proceed towards Coochbehar town by defying prohibitory orders, Darjeeling SP Rajiv Mishra said.

Police resorted to firing to disperse the mob, holding an agitation under the banner of Great Coochbehar Peoples Association, which also damaged 30 police vehicles and pelted stones at policemen, seriously injuring Ahmed, he said.

Ahmed was rushed to a nursing home in Siliguri where he was pronounced death, Inspector General of Police (Law and Order) Raj Kanojia told PTI in Kolkata.

He said at least 12 police personnel were injured - three of them seriously - in the mob violence. The IGP said curfew had been clamped in the area in view of heightened tension.

Altogether 650 arrests were made, he said, adding that state armed police and Rapid Action Force personnel had been deployed at Khagrabari.

The demands of GCPA include the formation of an interim government in Coochbehar district. It also sought the West Bengal government to not conduct any election in the district as 'the terms of incorporation of Coochbehar into India had been violated'.

The transfer of administration of the princely state of Coochbehar to the Union of India came into force on September 12, 1949 and it was merged with West Bengal on January 19, 1950.