Hundreds of parents have stormed a primary school in south-western China after learning their children were being fed rotten food, clashing with riot police and refusing to leave.

Parents of students attending the Chengdu No 7 Experimental school, a private institution with an intake of about 6,000, discovered issues with school lunches after their children experienced breathing problems and stomach pains.

A doctor who inspected one student said the child appeared to have been eating rotten food for a prolonged period of time, according to one parent’s social media post. Some parents discovered supplies of frozen meat and produce growing mould and posted about them online.

On Tuesday night, parents gathered outside the school. Footage shows crowds pushing over a metal gate and rushing into the school. On Wednesday, parents continued their protest, arguing with school administrators and officials. In one video, a man grabs the microphone from a local education official attempting to talk and slams it on the ground.

Public health scandals affecting children are especially sensitive in China, where more than 200,000 faulty vaccines for children were discovered last year. In 2008, six children died and more than 50,000 infants were treated in hospital after drinking melamine-laced milk powder.

Classes have been suspended; local authorities said the food had been sealed off and teams sent to investigate. “No matter who they are, they will be seriously dealt with and will not be tolerated,” said the local government in Wenjiang district, where the school is located.

News of the food scandal spread quickly on Wednesday, with parents and a growing number of online supporters appearing increasingly upset over the response from authorities. Footage posted online shows police tackling protesters. In one video, police with riot shields tear a banner away from a group of women. One parent said the police had pepper-sprayed them, and videos showed men crouched over and wiping their eyes.

The topic, which at the beginning of the day had more than 200m views on Weibo, has begun to be censored. Online users continued to repost photos and videos, even as they were being taken down.

In one video, a woman yells into a microphone: “I’m not afraid to go to jail. I’m not afraid to break the law … as a mother, I just want to see my son healthy.” In another, a mother proposes that they cook a meal with the ingredients used for the student meals and feed it to the officials. “Let them taste it,” she says.