Four children died in Puyang city, Henan province on Monday, after an overloaded kindergarten school bus caught fire, local authorities said on June 12.

The accident is being investigated.

Thirteen children were on the eight-seat minibus when the accident happened in Zhangyi village at around 6 pm, according to an official with the Puyang government’s information office.

Two children and the driver were severely injured. Two other children and a person involved in the rescue operations suffered minor injuries.