Chongqing is adding thousands of surveillance cameras within the municipal districts as part of local authorities' move to strengthen the public security system.

The new project, with an investment of 5 billion yuan ($0.75 billion), will be the largest video management system construction project under way in China.

"The surveillance system will provide sufficient support to Chongqing's public security management. The system will be used for disaster alarms and work safety supervision, as well," Chongqing Mayor Huang Qifan said at a ceremony where municipal government officials signed an agreement with China Electronics Technology Group Corp to implement the project.

The number of surveillance cameras installed will total 500,000, including several thousand cameras already in operation, a local government official said. All cameras are expected to be linked with each other via a public information platform to strengthen the city's security network.

The camera system will automatically respond in case of out-of-the-ordinary activities such as someone illegally climbing over a fence, the presence of a masked man, someone spying on someone else or a fire disaster, the official said.

Authorities said the installation will be limited to the public places such as large outdoor squares, hospitals, schools, parks and tourist zones to ensure that personal privacy is protected. Cameras also will be installed in high crime areas. Signs will remind residents where cameras are in operation.