An explosion at a plate plant operated by Baogang United Steel in Baotou, Inner Mongolia autonomous region, killed two people and left five others missing, local authorities said Sunday night.

The blast occurred around 3 pm Sunday at the Baogang rare earth steel plate plant. As of 5:30 pm, 66 people had been taken to hospitals for treatment, including three in critical condition, according to information released by local emergency management and fire rescue authorities.

The regional Party committee and government launched an immediate emergency response, dispatching rescue teams to the site to carry out search and rescue operations.

Wang Weizhong, Party secretary of Inner Mongolia, and Bao Gang, chairman of the regional government, issued instructions and rushed to the scene to oversee rescue efforts.

Wang called for scientific search and rescue operations, full medical treatment for the injured, strict prevention of secondary risks, and a swift investigation into the cause of the accident.

Baogang United Steel also ordered all-out efforts to search for the missing, verify casualties, and treat the injured.

The cause of the accident is still under investigation.