At least 30 people were killed and 38 injured, many of them suffering severe burns, in a fire in a chemical plant in central Iran on Sunday, the state news agency IRNA said.

The fire in the cosmetics and detergent-producing plant near the town of Shazand was caused by a blast during welding work in a reservoir, IRNA said.

The accident happened at 4 pm (1130 GMT) in the plant near Shazand in the provice of Markazi, about 320 kilometres (200 miles) south of Tehran.

"Witnesses said a 60,000-litre chemical reservoir exploded," IRNA said, adding that all the equipment in the factory and its adjacent plant caught fire.

A local rescuer told IRNA that the injured were rushed to a nearby hospital and that 23 people had suffered 70 to 100 percent burns.

Markazi province is one of Iran's main industrial hubs. It is also home to one of Iran's key nuclear sites, a heavy water reactor which is under construction near the city of Arak.