One person died and five others were injured after a blast occurred on Thursday at Trinamool Congress party office in West Midnapore district in West Bengal.
The identity of the deceased and the injured was not immediately known, they said.
The explosion took place at around 10 am.
According to the agency reports, the injured were admitted to a hospital and the police cordoned off the area.
The sources said it was also not known whether a crude bomb had exploded or a gas cylinder inside the party office led to the incident.
Pradyut Ghosh, TMC MLA of Narayangarh, said that the cause of the explosion could not be ascertained till noon and the police were looking into it.
PTI