A man was killed in an explosion at an office of the Trinamool Congress in West Midnapore district in West Bengal, India on Thursday morning.
According to an NDTV interview with local police, five others who were injured in the blast were all admitted to hospital for treatment.
Police were not immediately sure of what caused the explosion, which reportedly happened at around 10am at the district office of state Chief Minister Mamata Banerjee's party, 130km from Kolkata.
Photos of the explosion site show twisted metal rods and chunks of concrete strewn on the ground in front of the Trinamool Congress office, as policemen walked about the compound to gather evidence.
People familiar with the matter said it was still not clear whether a crude bomb or a gas cylinder inside the office had caused the explosion.
As of Thursday afternoon, Trinamool legislator Pradyut Ghosh said the cause of the explosion could not be ascertained and police were looking into it, news agency Press Trust of India reported.