Washington, Sep 22 (IANS): An American businesswoman accused of stealing state secrets has been formally arrested in China, six months after she was detained there, her husband and a family lawyer said on Tuesday.

The detention of Phan Phan-Gillis, 55, from Houston in Texas went unreported until Monday. It came to light shortly before Chinese President Xi Jinping was to arrive in the US, The New York Times reported.

Phan-Gillis disappeared in March when she was accompanying a delegation of officials from Houston in southern China. She is a US citizen, born in Vietnam and of ethnic Chinese heritage.

Phan-Gillis’ husband Jeff Gillis said he learnt of her arrest on Sunday.

Jeff Gillis said he hoped that Xi’s visit would open opportunities for the US administration to press for her release after months of secretive and fruitless efforts on his own.

He said he did not know the details of the accusations but said claims that his wife was involved in espionage was ludicrous. “Sandy (Phan-Gillis' nickname) is not a spy,” he said.

“Sandy is a hard-working businesswoman who has spent years doing non-profit-type work to build Houston-China relations,” he said.

Simon Tang, a lawyer based in Houston, confirmed that Phan-Gillis had been “formally arrested a few days ago” after months in secretive detention in Nanning, capital of Guangxi region.