Chinese authorities say they are investigating an American businesswoman on suspicion of threating China's national security, confirming earlier media reports that Phan Phan-Gillis of Houston has been detained.

Foreign ministry spokesman Hong Lei said Tuesday that Beijing is handling the case of Phan-Gillis according to China's laws. He said the woman was healthy.

Phan-Gillis is a Vietnamese-American of Chinese descent. The Houston Chronicle reported Monday that the woman was in a trade delegation to China when she was stopped on her way to Macau.

Her husband, Jeff Gillis, told the Chronicle that he was publicizing her six-month detention just as Chinese President Xi Jinping is visiting the U.S. this week in hopes of pressuring Beijing and Washington to secure her release.