An American businesswoman held in China since March last year has been charged with spying, China's Foreign Ministry said on Tuesday, the latest development in a case that has added to U.S.-China tensions.

Sandy Phan-Gillis, from Houston, Texas, who is of Chinese ancestry and is a naturalized U.S. citizen, was arrested in March 2015 and had been held without charges since then.

"Based on our understanding, Phan-Gillis, because of her suspected crimes of espionage, has been charged according to law by the relevant Chinese department," Chinese Foreign Ministry spokeswoman Hua Chunying told reporters at a regular briefing.