The toll in the explosion at a fireworks manufacturing unit at nearby Padukkad in Thrissur district of Kerala on Thursday, has gone up to seven with three more workers succumbing to their injuries on Friday.

At least 13 persons were inside the unit when the explosion took place. Six workers, who were injured, have been hospitalised and the condition of two is said to be serious, police said.

The fireworks were being manufactured for the Paramekavu Devaswom for the May 7 Thrissur Pooram festival. The mishap occurred when the workers were making final preparations for the sample fireworks, which was to be held on Friday.

Irrigation Minister Thiruvanchoor Radhakrishnan, who visited the spot and the hospital where the injured have been admitted, told reporters that a magisterial inquiry has been ordered into the incident. The government was of the opinion that the fireworks display this year should be done away with following the mishap.

Stern action would be taken against those who had violated the terms and conditions stipulated in the license, he said.