Updated

The wife of a pro-democracy activist detained in China says she has been prevented from flying to the mainland to demand a visit with her husband, whose case has inflamed cross-strait tensions.

Li Ching-yu told reporters that airline staff told her Beijing authorities had canceled her Chinese-issued travel permit when she tried to check in on Monday. Li had hoped to fly to China to demand information about her husband, Li Ming-che, who has not been heard from since March 19.

A Chinese official said last week that Li is under investigation on suspicion of endangering Chinese national security and is in "good physical condition."

Li, a college employee who used social media to discuss China-Taiwan relations, is the first Taiwanese activist in years held by China on security charges.