HOHHOT -- The death toll has risen to nine following a blast at a steel plant in North China's Inner Mongolia autonomous region, with one other person still unaccounted for as rescue efforts continue, local authorities said Tuesday.

The explosion took place at 3:03 pm Sunday at a plate plant of Baogang United Steel in Baotou city, according to the on-site emergency rescue headquarters. Previous reports show that the blast originated from a 650-cubic-meter saturated water and steam spherical tank.

Verification of the missing person is ongoing.