HOHHOT, March 29 -- A total of 11 people suspected of causing an explosion in a residential building in northern China's Inner Mongolia Autonomous Region have been seized, local police announced Wednesday.

The accident at about 2 p.m. Saturday in a multi-storey residential building in Tumd Right Banner, Baotou city, caused part of the building to collapse.

Five people were killed and another 25 injured in the incident.

Police said the explosion might have been caused by illegal storage of explosives.

Further investigation is ongoing.