Six persons were killed and several others were critically injured in a blast at a plastic factory in West Bengal's Malda district on Thursday, police said.
The incident took place in Sujapur area around 11 am, news agency PTI reported quoting a senior police officer.
Preliminary investigation has found that a technical fault in a heavy machine inside the factory caused the high-intensity blast, police official Alok Rajoria said.
"The explosion happened during plastic manufacturing. We are probing all the angles and a forensic team will visit the spot," he said.
A huge police contingent has been sent to the spot to bring the situation under control. Fire tenders are trying to douse the blaze and rescue survivors, the official said, adding an investigation has been started.
Chief Minister Mamata Banerjee has announced a compensation of Rs 2 Lakh for the family of those who died and Rs 50,000 for the injured.
Senior Minister Farhad Hakim has been sent to the spot to take the stock of the situation.
Governor Jagdeep Dhankhar expressed anguish over the incident and asked Chief Minister Mamata Banerjee to "contain illegal bomb-making" and ensure "professional non-partisan investigation".
"Anguished at deaths in reported blast that ripped establishment apart at Sujapur area of Malda district. According to SP five killed & five injured. Time @MamataOfficial to proactively contain illegal bomb making and ensure professional non partisan investigations @WBPolice," he tweeted.
Mr Dhankhar also asked the administration to ensure medical assistance to the injured.