SHANGHAI, April 20 -- More than 1,000 policemen in Shanghai began carrying revolvers while on patrol Sunday as China tightens public security to deal with serious violent crimes.

The Ministry of Public Security invested in the firearms and specially designed them for its police force. The police officers qualified to carry them after a training series and examinations on laws and psychology, according to the municipal public security bureau.

The police will carry out routine patrols in densely populated areas like urban centers and transport hubs.

Chinese police generally do not carry guns and gun crime is rare in China, which has tight control on firearms.

Following the fatal knife attacks in Kunming and Changsha, the ministry said in mid-March that it would carry out armed patrols and take timely measures to handle violent crimes.

Public security organs at all levels are urged to increase work efficiency and further improve the emergency command mechanism in order to fight crime.

In addition to Shanghai, the ministry named some other key cities, such as Changsha, Kunming, Urumqi and Lhasa, where public security will be reinforced to effectively prevent and crack down on criminal activities.

The ministry also launched a three-month program in early March to train policemen in using firearms in accordance with the law.

Training mainly focuses on policemen who patrol streets and handle emergencies in big cities and county-level regions.