Another seven were injured and were being treated in hospitals for burns and smoke inhalation.
"On Wednesday night, two of the six injured, sent to Nagpur for treatment, succumbed to their injuries", he said.
Police sources said the death toll may further go up with bodies of victims still being extricated from the blast site. "We could see at least a dozen more in the debris inside the factory", said a senior police officer.
The cause of blasts and subsequent fire inside the factory was yet to be known.
According to district collector Bharat Yadav, the incident took place in Kheri village, which is almost 10 km from the district headquarters. "The post-mortem on the bodies have been conducted and then samples from the spot were also collected". Workers were present there when the fire started.
Hospital authorities said some of the bodies were charred beyond recognition.
Madhya Pradesh Chief Minister Shivraj Singh Chouhan has announced a compensation of Rs 2 lakh each to the next kin of the deceased.
Firefighters doused the flame completely by Wednesday evening.
Fire officials took 3 hours to extinguish the fire.
Yadav said the factory was located away from the human settlement.
Workplace accidents are common in India, where poor safety standards and lax enforcement of regulations contribute to accidents and fatalities. As reported by the Times of India, negligence of one of the workers who allegedly threw a half burnt bidi on the pile of crackers led to the explosion.
India has a huge demand for firecrackers, which are used in religious festivals and weddings.