Legal experts are calling for greater supervision of weapons after a handgun accidentally fired during a safety awareness demonstration held by two police officers at a kindergarten in Henan province.

The two police officers were holding the demonstration on personal safety and violence prevention at the school in Zhengzhou on Thursday to celebrate International Children's Day, which falls on Sunday.

The gun accidentally fired into the concrete surface on which they were standing, creating debris and sparks that struck the legs and arms of four parents and a child. They suffered light injuries and were sent to a hospital.