Police said it got information about a chocolate bomb being hurled at the TMC office at Phiringi More in the town but no formal complaint had been lodged by either side.
TMC leadership alleged BJP supporters hurled crude bombs but there was no injury as the came out of the office.
The supporters themselves put off the flames, the TMC said.
BJP said no missile was hurled at TMC office.
The incident came close on the heels of clash between TMCP and ABVP at Kalna College over union elections.

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