Eight people have died of suffocation in a refrigerated truck in Henan province, a local investigation team said.

They were found unconscious when the vehicle arrived at a petrol station on Saturday evening in Hongzhuangyang Township in Yexian County.

The victims were confirmed dead in the small hours of Sunday.

According to Xinhua News Agency, the eight had stayed in the insulated compartment of the vehicle, which was against regulations.

It was not immediately clear if they were Chinese nationals or foreigners.

The truck driver and other "responsible personnel" have been detained, authorities said.

They said the case was being investigated. (Xinhua/AFP)