At least seven people were killed and seven others injured in a powerful explosion at a firecracker factory in southern Sindh province, officials said on Sunday.

The blast occurred in Laghari Goth in Hyderabad district on Saturday evening, Hassan Ul Haseeb, spokesperson for Rescue 1122 Sindh, told Xinhua.

“The explosion triggered a massive fire that quickly engulfed the factory,” Haseeb said.

Rescue teams recovered the bodies from the debris and shifted the injured to a local hospital. Three of the wounded were in critical condition.

Authorities said the cause of the explosion was still under investigation.