Malappuram (Kerala), Nov 1 (IANS): A blast rocked the Collectorate premises here on Tuesday afternoon but no casualties or damage were reported, police said.

The bomb, kept in a pressure cooker, was placed beside the vehicle of a state government official who came for a routine meeting at the District Collector's office, said police

Malappuram Superintendent of Police Debesh Kumar Behra, who reached the scene soon after the explosion, told reporters that it was a 'pressure cooker bomb' and apart from the vehicle, no other damage or casualties were reported.

"A box with a name slip of 'The Base Movement' has been recovered from the site. It seems this organisation was involved in such activities in Nellore, Mysuru and Kollam in the past," he said, adding that a special investigation team will be set up to probe the incident. 

Behra also said that presence of ammonium nitrate, used in the bomb, has also been identified.

District Collector A.Shinemol, who was also at the scene, incidentally held the same position in Kollam last year when a similar explosion took place at the district headquarters there.