China's public security authorities have installed more than 210,000 annunciators and surveillance cameras at "key areas" by the end of 2005 to monitor and prevent crimes.

The devices have helped prevent and monitor over 200,000 crimes of various kind so far, Zheng Shaodong, assistant minister of the public security, said Tuesday at a press briefing.

The alert devices and cameras were placed mainly at major public sites and important institutions including busy traffic centers, banks and government office buildings.

Experts said that the monitoring video cameras only account for a small number of the widely used surveillance facilities in China.

Early reports said that Beijing already has 263,000 surveillance cameras around the city that not only monitor traffic flow on major roads but also keep watch on back alleys and entertainment venues.

Source: Xinhua