SACRAMENTO (BLOOMBERG) - A Chinese researcher in US custody on charges of visa fraud was ordered detained until Aug 10, when she'll have a fight on her hands if she asks to be released on bail.

Tang Juan appeared Monday before US Magistrate Judge Deborah Barnes in Sacramento, California. She took shelter at the Chinese consulate in San Francisco after federal agents interviewed her at the University of California at Davis about allegedly lying about her military service.

Officials haven't explained how she came to be in federal custody last week. The Chinese Foreign Ministry has called her case a "political persecution." At a hearing Monday, Ms Lexi Negin, a federal defender representing Tang, told the judge she hasn't been able to collect the information required to request Tang's release on bail.

Judge Barnes set the hearing next month before US Magistrate Judge Edmund Brennan to review a possible bail package. Assistant US Attorney Heiko Coppola told the judge the US will argue against Tang's release.

As the US and China have sparred publicly by closing each other's consular offices in Houston and Chengdu, the Justice Department is investigating universities across the US in an attempt to uncover members of China's military forces who it says are hiding in plain sight.

Prosecutors last week highlighted other recent criminal complaints and arrests of other Chinese scholars that the US says are working for China's People Liberation Army.