An explosion caused a chemical plant in southwest China's Chongqing municipality to catch fire early on Friday morning, local authorities have said.

No casualties have been reported so far after the acetylene-burning blast happened at 3:30 a.m. at a workshop of Fangxin Fine Chemical Co. Ltd. in Jiangbei district, said a spokesman with the district government.

The fire has been controlled, and the cause of the accident is being investigated.

The company is a holding subsidiary of Southwest Pharmaceuticals Co., Ltd.