Five men were poisoned to death by carbon monoxide Wednesday at their residence in north China's Inner Mongolia Autonomous Region, the local government said.

The victims were migrant workers living in a rented house in Lanbuta Village of Hohhot, capital of Inner Mongolia.

An initial investigation by police showed that the five were burning coal for heating in the house without a chimney, which led to the accumulation of carbon monoxide, the municipal government of Hohhot said.

The five, aged between 19 to 54, were natives of the southwestern Sichuan Province and the northern Hebei Province, police said.