china police
A man stabbed 20 schoolchildren in Beijing’s Xicheng district. In this image, Chinese police patrol in front of the Canadian embassy in Beijing, Dec. 13, 2018. GREG BAKER/AFP/Getty Images

UPDATE: 3.15 a.m. EST - A former school maintenance worker told a local daily that the attack was carried out by a 49-year-old temporary janitor who was angry at not having passed his probation. A parent said the attack took place while the children were doing exercises on the school running track.

"The attacker was standing nearby and used a hammer-like weapon to hit the children’s skulls one by one, before he was stopped by the PE teacher," the parents said.

Security was beefed up at the hospital where the children are admitted to and nurses were "rushing in and out of the operation rooms," a hospital bystander said.

Original story:

A staff member stabbed 20 children of a primary school in Beijing’s Xicheng district on Tuesday morning. The man is now in police custody.

Xicheng police, on its official Weibo page, said the incident took place around 11.15 a.m. local time Tuesday (10.15 p.m. EST Monday) at Xuanwu Normal Experimental Affiliated Number One Primary School. Though three students were seriously injured in the attack, none of them had life-threatening injuries, the police said, the South China Morning Post reported. The other injured students were admitted to the intensive care unit at a nearby hospital.

“The mayor today came to the hospital to wait with us while the children were being medically treated. We have paused several operations to save all the children,” a doctor at the Xuanwu hospital said.

The school management informed parents that a "school worker” had carried out the attack. However, there is no clarity yet on the type of weapon used by the man.

“A worker at our school attacked 20 students in a first-floor stairwell. It is not like what everyone is saying, he did not use a knife. Everyone please keep calm. Second grade classrooms are on the first floor, it was children from those classes. The children were immediately rushed to hospital. We have been communicating with parents but some of them have gone to the hospital to see their children. At the moment, if we have not called you, your child should be safe," the head teacher of the school said.

Earlier in the day, videos from the scene showed parents demanding details from the staff members at the school gates, others took to social media to give out information.

“The details are still not clear. They were all younger students and were stabbed by an adult,” wrote one parent on WeChat at the time.

This is a developing story.