BEIJING -- Chinese citizens must register their identities when they buy potentially deadly knives, the country's Ministry of Public Security (MPS) said here on Tuesday.

The knives under control include daggers with blood grooves, lock-knives, knives with blades measuring over 22 centimeters, and those with blades over 15 centimeters and a blade point less than 60 degrees, the ministry said in a circular posted on its website, www.mps.gov.cn.

Police departments at all levels should check knife manufacturers for illegal production of deadly weapons.

Regulations concerning knife tools used by China's ethnic groups are to be set by local autonomous governments, the report said.