At least six persons were killed and another 5 still missing, besides seven injured in massive fire followed by multiple explosions in a pharmaceutical factory at Mahad MIDC on November 3, a police official said here on Saturday.

The fire, the cause of which is not clear yet, quickly spread and led to several explosions in the factory premises of Blue Jet Healthcare Ltd., spread over more than eight acres of land in the Mahad MIDC complex.

A portion of the pharmaceutical factory where around 20 workers were on duty at the time on Friday morning, was engulfed in the blaze with thick dark smoke emanating from there.

Soon after the blaze at around 11 am, deafening blasts were heard in the vicinity and Raigad Police and local fire brigade teams, and later last night the NDRF, rushed to the relief and rescue.

"Of the fatalities, we have recovered four bodies so far… Search is on for the other victims," Raigad (Mahad) SDPO Shankar told IANS from the disaster spot.

Other officials said that the conflagration has considerably weakened the factory structure making it very risky for the NDRF, fire brigade and other teams to carry out the rescue mission.

Guardian Minister of Raigad Uday Samant visited the spot around midnight of Saturday and instructed the officials to trace out the remaining victims and ensure proper medicare for the injured.

Preliminary reports suggest a suspected gas leak may have led to the blaze and the explosions resulting in chaos as the flames started spreading in other units within the factory premises, said an eyewitness.

Among the seven injured, the condition of two is stable and three others are reported to be critical at the Mahad rural hospital where they are being treated.