A video of the incident has surfaced on Weibo

An explosion outside a kindergarten in Xuzhou, China, has killed at least 8 people and injured 70.

Pictures of injured people outside the Chuangxin kindergarten in Jiangsu province have circulated on Chinese social media, as well as a video of the explosion.

Mayor of Xuzhou, Zhou Tiegen, said none of the casualties were from the kindergarten.

“We’ve checked and at the time of the explosion, the Chuangxin kindergarten still hadn’t been let out of class, and none of the children or teachers from the kindergarten was a casualty,” Mr. Zhou said, according to the website of Legal Daily, an official Chinese newspaper.

Mr. Zhou added that the police had “made an initial determination that this is a criminal case, and are tentatively focusing on a suspect.

The Telegraph reports that the bomb was made by a 22-year-old man who died at the scene. The local public security bureau reportedly found carvings on the wall of a home rented by the suspect, surnamed Xu, which said “death”, “kill” and “extinct.”

Police also found materials to make bombs in the property. They added that the suspect  lived and worked near the nursery. The man had dropped out of school because of an autonomic nervous system disorder, involving dizziness and problems with basic bodily functions

NY Times reports that hospital workers in Xuzhou said that the majority of people injured were parents or grandparents who were waiting to collected their children from school. Some had toddlers waiting with them too.

An anonymous woman said she searching for her sister who was waiting outside the school when the incident occurred. She dialled her sister’s phone number but was not able to get through.

Two months ago, China premier Li Keqian reassured the public about school safety, “Campus safety concerns the healthy development of millions of students and the happiness of their families.”