A US businessman is under arrest in China, accused of spying for Taiwan, according to the US embassy in Beijing.
Xie Chunren, who was born in China, has been kept under house arrest without charge for nearly three months, after his arrest in Sichuan province in May.
Mr Xie's detention is the latest in a series of such cases.
The embassy said it was informed of his detention shortly after his arrest on 31 May, but he had only now agreed to have his case made public.
Both Taiwan and its rival China are believed to run extensive intelligence networks in each other's territory, and both sides regularly announce the arrests and convictions of alleged spies.
Earlier this month, a Hong Kong journalist was formally charged with spying for Taiwan.
Ruled by separate governments since 1949 end of civil war
China considers the island part of its territory
China has offered a "one country, two systems" solution
Most people in Taiwan support status quo
Beijing sees Taiwan as part of its territory and has threatened to invade if the island formally declares independence from the mainland.
It is not clear exactly what Xie Chunren is accused of, but his son, Xie Yuanyang, told the International Herald Tribune that his father's detention might have something to do with an investigation into one of his former acquaintances, David Wei Dong.
He said he could not think of any other reason for his father's arrest.
Mr Dong, a US citizen, was arrested in the southern city of Guangxhou in 2003 on spying charges.
State media said at the time that he was suspected of providing Taiwan's military intelligence with information about China.
The US embassy said it was following Mr Xie's case closely to ensure his rights were respected.