China says it might now detain American nationals inside China.
This is in retaliation for the DOJ prosecution of Chinese military affiliated "scholars".
"According to the Journal, the sources confirmed that over the summer, the U.S. began detaining Chinese scientists conducting research at American universities over charges of concealing to U.S. immigration authorities their active duty statuses with the People’s Liberation Army."
https://thehill.com/policy/international/china/521566-china-warns-it-will-detain-american-nationals-following-doj
"According to the Journal, the sources confirmed that over the summer, the U.S. began detaining Chinese scientists conducting research at American universities over charges of concealing to U.S. immigration authorities their active duty statuses with the People’s Liberation Army."
https://thehill.com/policy/international/china/521566-china-warns-it-will-detain-american-nationals-following-doj