Eleven people have died after the roof of a school gymnasium in China collapsed while it was being used by a girls' volleyball team.

state media reports said Many of the victims are children, parents have thronged a nearby hospital seeking updates.

Only eight of the 19 people who were inside the gym in the industrial province of Heilongjiang survived.

A preliminary investigation found that perlite, a form of volcanic glass, had been illegally piled on the roof soaking up rain water, which caused the collapse at 15:00 local time.

The coach of the middle school's girls' volleyball team was heard calling out the students' names as rescue teams clawed through the rubble in Qiqihar city, the Media reports.

Lax safety standards and poor enforcement have made industrial accidents common in China.

Construction accidents are also common in the country and have been blamed on lax safety standards and poor enforcement.

In June, an explosion at a barbecue restaurant in north-west China killed at least 31 people. A preliminary investigation found that a restaurant employee was replacing a broken valve on a liquefied gas tank when the blast occurred.