Officials said rescue efforts were complete. They did not reveal details of the victims but several Chinese media outlets reported that most were school children.
A widely circulated video filmed inside one of the hospitals where the injured were treated showed a man claiming to be the father of a dead pupil who said no one from the local government, the hospital or police had updated parents about the rescue progress for five hours.
Other parents in the video echoed his complaints about the lack of transparency.
The father’s ordeal drew an outpouring of sympathy online, with people reposting the video on social media and asking why the parents were not allowed to know what was happening to their children.
The collapse happened at about 3pm on Sunday. A Xinhua video on Sunday evening showed the roof of the reinforced-concrete gymnasium completely destroyed.
Qiqihar, which is 1,300km (810 miles) northeast of Beijing, has a population of 5.12 million and experienced heavy rain on Sunday, according to the National Meteorological Centre.
Chongqing-based news service Cqnews.net cited several sources who said a girls’ volleyball team was training in the gym when the roof fell.
A witness told an online video outlet affiliated with China Youth Daily there was “nowhere to hide” from the overhead collapse inside the gym.
Some media outlets raised questions about construction standards and about how well-maintained school buildings were.
An opinion piece published by The Beijing News on Monday afternoon asked the local government “where are the construction regulations?”.
Changjiang Daily, Wuhan’s official newspaper, posted on Weibo that the authorities should clarify whether the gym, which was built in 1997, was a “tofu-dreg” project, a widely used idiom for poorly constructed buildings.
China Youth Daily reported that the girls were training over the summer holidays because they were expected to go to Hubei province for upcoming games.
The collapse happened about 3pm on Sunday. Photo: Weibo
The official WeChat account of Qiqihar No 34 Middle School posted an article on Saturday celebrating the team’s second place in a provincial competition.
According to Heilongjiang Daily, the construction company involved did not build the gymnasium but was overseeing a new school building next door.
It said the company stored building materials made of perlite on the gym’s roof, which had collapsed after it started raining.
Perlite is a highly absorbent mineral used in construction, industry and agriculture.
An engineering expert who teaches at China Agricultural University said on his personal social media page that perlite could weigh 10, or even 25, times its original weight when soaked with rainwater, “greatly increasing roof loads and potentially leading to the collapse”.