The explosion occurred on Saturday morning in Inner Mongolia's Sijiazi township, destroying 50 workshops at the Xinxin Fireworks Plant, Xinhua news agency said.

The blast occurred as workers at the plant were weighing and mixing ingredients for making the fireworks, the report said.

According to a preliminary investigation, safety regulations at the plant were being violated at the time of the blast, the report said without providing details.

China has a huge fireworks industry that is notorious for its lax safety standards. -- AFP