Suri: An explosion ripped through a Trinamul office in Birbhum's Kankartala on Monday morning, flinging the door and windows 35ft to 40ft away.

None was in the office at the time of the blast which was allegedly caused by crude bombs stocked inside.

The stockpile was linked to a purported Trinamul factional feud over spoils of theft of coal from abandoned mines in the area and selection of pradhan of the uncontested Barrah gram panchayat.

Birbhum district Trinamul chief Anubrata Mondal said BJP activists from Jharkhand had hurled bombs at the office.

The BJP said the charge was "ridiculous". "How can BJP workers go and keep bombs inside a Trinamul office at a time we could not file nominations during panchayat polls?" asked BJP district president Ramakrishna Roy.

The interior of the single-storey office at Barrah village was turned into debris in the impact of the blast with the roof hanging precariously. "The intensity of the explosion was so high that windows and the iron door of the building were flung nearly 40ft away. There was no one inside the office at the time of the blast," a resident of Barrah said

Police sources said the impact showed that the blast had occurred inside the building.

A police officer said it appeared that a large number of crude bombs had been kept inside the office and they had gone off accidentally.

District police chief Kunal Aggarwal said: "We have started a probe. No one has been arrested so far."

The incident comes a few days after three Trinamul workers died in an explosion in a party office in West Midnapore's Narayangarh on August 23.

The Trinamul office at Barrah had been set up in 2012.

Trinamul sources have said there are two factions in the party in Khoirasole block under which Kankartala police station and Barrah village fall. "One group is led by Dipak Ghosh, the block committee president, and the other by Abdul Haque Kaderi, the working president of the block committee," said a Trinamul leader.

In the panchayat elections in May, all seats in Khoirasol block were won uncontested by Trinamul, including Barrah gram panchayat.

"A week ago, after a meeting in the district Trinamul office in Suri, Nadera Biwi was declared as the pradhan of Barrah gram panchayat. Biwi is a loyalist of Ghosh and the choice was opposed by the Kaderi faction," said the Trinamul leader.

The sources said there had been a long time feud between the two lobbies over control of coal theft from abandoned mines.

"Barrah is known for illegal coal smuggling. Fights with bombs and bullets between the two factions happen regularly. The Trinamul office was once under the control of the Kaderi group and is managed by the Ghosh lobby now. After the name of the gram panchayat pradhan was declared, both the groups were stockpiling crude bombs for a showdown," a senior Trinamul leader in the district told The Telegraph.

"A local leader Asfar Sheikh alias Kalo, a Ghosh loyalist, runs the party office," he added.

Kaderi said: "The party office was not under our control. Kalo can explain how the bombs were stocked in the office. I can only say despite being the working president of the Trinamul block committee, not a single candidate from among my followers was fielded as a gram panchayat candidate."

Kalo could not be contacted as his phone was switched off and Ghosh did not take calls.