An inspection of Beijing's bunkers and underground architecture has found 2,600 of its 20,000 sites vulnerable to terrorist attack.
The inspection, the largest since 1949, was part of China's anti-terrorist efforts following the September 11 attacks, said the China Police Daily, a publication of the Public Security Ministry.
Some of the problem areas were closed after the inspection, but the report did not give numbers.
Xinhua said Beijing planned to develop a computerised management system involving a three-dimensional electronic map of all underground tunnels and housing in Beijing, with the first phase to be launched in the Chaoyang district in June. Closed-circuit television and alarm systems will be installed this year in at least a quarter of the sites considered subject to terrorist attack, such as underground shopping malls and museums.
Inspectors also found some sites had been illegally renovated, causing fire safety and other security problems.
Mainland cities have extensive underground tunnels and air-raid shelters that millions of Chinese were assigned to build in the 1950s and 1960s, fearing military attack from the United States and the then Soviet Union.
Beijing has been the target of a series of bomb attacks in the past decade, many of them allegedly launched by Xinjiang province separatists.