Analysts said China's rare and swift admission of the espionage scandal could cast Taiwan President Chen Shui-bian as irresponsible and hurt his March 2004 re-election bid.

Hong Kong's Ming Pao daily reported this week that Chinese authorities had swooped on a spy ring after Chen made public, with pinpoint accuracy, the location of Chinese missiles aimed at the island. Chen's spokesman has defended the president, saying it was public information.

Beijing and Taipei have been spying on each other since their split at the end of the Chinese civil war in 1949. Beijing considers Taiwan a breakaway province that must be brought back to the fold and has vowed to attack the self-ruled democratic island of 23 million if it formally declares independence.

"What these spies did may bring catastrophes and bitterness to the people of Taiwan," China's official Xinhua news agency said Wednesday, quoting a state security spokesman.

The Taiwan Defense Ministry's Military Intelligence Bureau earlier dismissed the Hong Kong newspaper report, saying nobody had been arrested.

Xinhua gave scant details of the alleged activities of those detained but said they had confessed to their crimes and all had "expressed their gratitude to the state security departments for the humanitarian treatment they have received."