Six people were killed and eleven others injured in an explosion at an illegal private firecracker factory in south China's Guangxi Zhuang Autonomous Region, local police said Sunday.

The blast hit the factory in a village in Lingshan County, Qinzhou City at about 6 p.m. Sunday, the police said. The cause of the explosion is being investigated.

Two people were killed on the spot while four injured died in the hospital after treatments failed.

Police said they have arrested a suspect surnamed Lao.

Authorities have ordered a city-wide crackdown on unlicensed firecracker factories following the incident.