"Recently, security incidents occurred at schools and kindergartens in many places, seriously threatening the life and safety of the teachers and students. Local education authorities need to direct schools to improve security and risk control mechanism, working with the police to deal with security issues around their facilities," the notice said.
Earlier in the day, local police said a 22-year-old suspect used an improvised explosive device to cause the blast. The suspect dropped out of school because of mental illness and is believed to have died in the blast.
China has recently seen a number of incidents at education facilities across the country. In late March, a stampede at an elementary school in the central Henan province left two pupils killed and 20 injured.