At least 10 people died when the roof of a school gymnasium in China's  Heilongjiang Province collapsed on Monday.

As of 5:30 a.m. Monday, rescuers had brought out 14 people from the debris. Among the casualties, four were confirmed dead on the spot, and six others died after full medical treatment, reports Xinhua.

The remaining four people suffered no life-threatening injuries.

There were 19 people in the gymnasium covering about 1,200 square meters at the No. 34 Middle School of Qiqihar in Longsha District when the accident occurred, reports Xinhua.

Four people escaped on their own and 15 were trapped, the municipal search and rescue headquarters told Xinhua.

A preliminary investigation found that construction workers illegally placed perlite on the roof of the gymnasium during the construction of a teaching building adjacent to the gymnasium. Under the influence of rainfall, the perlite soaked up water and gained weight, resulting in the roof collapse.

Those who were in charge of the construction company have been taken into police custody.