Local authorities have confirmed the identity of five children found dead inside a dumpster in Southwest China's Bijie city.

The autopsy results showed that the five boys, with ages ranging from 9 to 12 and from Bijie's Caqiangyan village in Guizhou province, died on Friday from carbon monoxide poisoning in a dumpster 1.5 meters long and 1.3 meters wide.

The children may have burnt charcoal to generate heat inside the dumpster, Xinhua News Agency reported.

The father of Tao Zhonglin, one of the victims, said that four of the boys had dropped out from school and usually ran away from their families for days to play.

Three weeks ago, the five boys ran away, leaving their families no message. The parents didn't hear about them until they were found dead by a trash collector.

The city government said that the children shouldn't have been allowed to drop out from school and should have been given more support by local officials in the weeks prior to the tragedy.

Authorities added that severe punishments have been given to officials from the district and to the headmaster of the school four of the boys attended.

The deputy head in charge of civil affairs and education of Qixingguan district, where the children lived, has been suspended from work.