A massive explosion at a steel plant in North China's Inner Mongolia autonomous region on Sunday afternoon left at least two people dead and five others missing, according to local authorities.

The blast occurred around 3 pm at a rare earth steel plate factory operated by Baogang United Steel in the city of Baotou. The force of the explosion — which sent plumes of heavy smoke into the sky — was so great that it shattered windows in several homes in the neighborhood.

As of 5:30 pm, 66 people had been taken to the hospital for treatment, including three in critical condition, according to information released by the local emergency management and fire rescue authorities.

Rescue teams from both the autonomous region and Baotou, including fire, police and specialized medical units, remained on the scene as the search continued for the five missing workers.

In the wake of the disaster, Inner Mongolia's top leadership has taken direct charge of the response.

Wang Weizhong, the region's Party secretary, and Bao Gang, chairman of the regional government, rushed to the site on Sunday evening to coordinate search operations.

Wang ordered prompt and scientific search and rescue operations. He called for necessary treatment of the injured, strict prevention of secondary risks, rapid determination of the accident's cause, and proper follow-up. Local authorities and relevant departments have been urged to put people and lives first, strengthen preventive measures, conduct comprehensive inspection of risks and hazards, and coordinate development with safety to prevent major accidents.

Bao also instructed that search and rescue operations be organized immediately, casualties be verified, and full efforts be made to treat the injured.

The cause of the accident was being investigated.

Baogang United Steel is a major State-owned iron and steel enterprise. What makes Baogang unique globally is its integration of steel production with rare earth resources.