At least four people were killed and several others injured in an explosion at a firecracker factory in the southern Indian state of Tamil Nadu on Saturday, officials said.

The blast took place in Banduvarpatti village near Sattur of Virudhunagar district, about 553 kilometers southwest of Chennai, the capital city of Tamil Nadu.

According to police, the victims were working in the factory when the explosion occurred. The blast also triggered a blaze in the factory.

It was not immediately known what caused the blast. Police have ordered an investigation into the incident.

(With input from Xinhua)