China's State Councilor Zhou Yongkang on Wednesday urged public security departments at all levels to improve the supervision of police services.

Zhou, also the minister of public security, said that -- as armed departments -- public security departments require stricter supervision than other executive departments.

"Inside public security departments, every power, every function and each individual policeman must be supervised," he stressed. "There are no exemptions."

He urged the branches responsible for supervising police services in public security departments to further improve their work, noting that the 17th national congress of the CPC and the 2008 Olympics are approaching fast.