HEFEI - Four people were confirmed killed and eight others injured in a factory explosion in East China's Anhui province on Tuesday, local authorities said.

A large pressurized equipment, which is used in brick making, exploded at about 11:20 am at Anhui Jiufu New Wall Materials Company in the economic development zone in Dangtu County of Ma'anshan City, according to municipal government officials.

Three people died on the scene. Of the nine injured people who were sent to hospital, one died after emergency treatment failed.

The cause of the explosion is not yet known.