A gun went off during a police safety talk at a kindergarten in the central Chinese city of Zhengzhou, injuring four adults and one child, police said.
The gun misfired during a demonstration and the bullet struck the ground, sending up sparks and cement that hit the arms and legs of bystanders, the city's Zhengdong police post said on its microblog.
The injuries were minor, the statement said. It said two police officers involved were confined as an internal punishment by the department, and that a deputy director, a squad chief and an instructor had been suspended.
Police extended "heartfelt apologies," it said.
Until recently, few Chinese police carried guns, but the government announced in April more will be issued firearms. It said they need to respond faster to violent criminals and other emergencies.
China has some of the world's most restrictive gun laws and prohibits almost all private gun ownership.