By Chris Hogg
BBC, Hong Kong
Taiwan says it has detained 17 military officers and civilians suspected of passing military secrets to China.
Taiwan officials said "damage limitation" was underway
They include an army major working in the defence ministry reported to be responsible for collecting intelligence about China's People's Liberation Army.
Taiwan says the alleged spy ring was discovered by accident during investigations into credit card fraud.
Both Taiwan and its rival China are believed to run extensive intelligence networks in each other's territory.
Both sides regularly announce the arrests and convictions of alleged spies.
Ruled by separate governments since end of Chinese civil war in 1949
China considers the island part of its territory
China has offered a "one country, two systems" solution, like Hong Kong
Most people in Taiwan support status quo
One of the suspects rounded up in the latest operation works in a Taiwanese defence ministry unit, which has access to sensitive information about the island's missile systems.
Officials have denied reports that the alleged spy, an army major, sold missile secrets to China.
When police searched his home, they found classified information about China's annual military drills, and unspecified scientific research his unit had collected.
Leaking this information, they said, could have allowed China to better understand Taiwan's intelligence-gathering operation on the mainland.
What they call "damage control mechanisms" have been activated. The investigations continue.