Four people were killed and three others injured after an explosion rocked a chemical plant in north China's Inner Mongolia Autonomous Region late Friday, according to local authorities, Xinhua reported.

The blast took place at around 11pm at a workshop of a chemical plant in Bayan Obo industrial park in Alxa League (prefecture).

The fire caused by the blast was put out early Saturday.

The regional government has set up a team to investigate the cause of the accident.