At least 11 people were killed and several others were seriously injured when a roof collapsed at a middle school gymnasium in China's far northeast collapsed late Sunday.

The incident occurred in the city of Qiqihar and the last victim was pulled from the wreckage Monday morning.

The official Xinhua News Agency said construction work at the school was the likely cause after workers stored materials on the gym's roof that absorbed rainwater.

Nineteen people had been in the gymnasium of the No. 34 Middle School, Xinhua said but gave no details on how many were students.

Social media and the Baidu news website carried footage of angry parents complaining about what they said was a lack of communication from authorities.

Such expressions of anger and defiance are usually quickly suppressed by police and government departments worried over social unrest.

Construction and industrial accidents are regular occurrences in China, largely resulting from companies ignoring safety standards and corruption or a lack of diligence on the part of local government agencies.

Those problems are especially acute in second- and third-tier cities such as Qiqihar, which lies in the Chinese rustbelt province of Heilongjiang bordering Russia that has seen large-scale economic decline and outward migration in recent years.