An explosion at a fireworks factory has killed at least 20 people in southern India.

Officials say Wednesday's blast triggered a massive blaze that swept through the fireworks plant in Tamil Nadu state.

Witnesses said huge plumes of smoke could be seen rising from the factory in the town of Sivakasi.

Authorities were pulling bodies from the debris, with some fearing that the death toll could rise. Several people were said to be injured.

The cause of the explosion is not immediately known.

Fireworks are often used during religious festivals and weddings in India.