At least nine workers were killed and several injured in a blast at an explosives factory in Nagpur, a central district in Maharashtra state on Sunday morning, a local police officer told Reuters over the phone.

The blast occurred around 8.30 a.m. (0300 GMT) at a factory run by Solar Industries India, the police officer surnamed Salve said. The factory manufactures industrial and military explosives, as well as propellants and warheads for India’s defense sector, according to Solar Industries’ website.

The injured were shifted to nearby hospitals, Salve said, adding that the number of casualties could increase. Salve was part of the team that went to the site of the explosion on Sunday morning.

The police are still investigating the cause of the blast, which occurred in the factory’s packing area.

Calls to a contact number on the company website were not answered, and email sent to the company did not receive an immediate response.