BEIJING — The death toll has risen to nine in Friday’s stabbing attack outside a middle school in northwestern China allegedly carried out by a former pupil seeking revenge for having been bullied.

The Mizhi county government in Shaanxi province reported that another 10 people have been hospitalized with injuries resulting from the rampage outside the No. 3 Middle School in the rural area that took place as classes were being dismissed for the evening.

Police have arrested a 28-year-old suspect identified by the surname Zhao who had been a student at the school and was apparently seeking revenge for having been picked on, the Mizhi government’s official microblog said on Saturday.

China tightly restricts private gun ownership, making knives and homemade explosives most common weapons in violent crimes.

Many schools have beefed up security at access points following violence against students and family members. In 2010, nearly 20 children were killed in knife attacks outside school gates, casting light on the medical system’s ability to diagnose and treat mental illness.

In June last year, a 22-year-old man made the bomb that exploded at the front gate of a kindergarten in eastern China, killing eight people, including himself.

Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.