An explosion at a factory in Inner Mongolia Autonomous Region on Sunday killed two people, left five others missing and sent 66 to hospitals, according to local authorities.

The blast occurred at around 3pm at a plate plant of Baogang United Steel in western Baotou City, causing noticeable tremors in the surrounding areas.

As of 5.30pm, local emergency management and fire rescue authorities reported two fatalities and five people missing.

Sixty-six individuals have been taken to hospital for treatment, three of whom are in a severe condition.

Rescue forces from both the autonomous region and the city have been dispatched to the scene.

The cause of the explosion is under investigation. (Xinhua)