The US has charged four Chinese nationals with visa fraud for allegedly lying about their membership of China’s armed forces.
Three are under arrest while the FBI is seeking to arrest the fourth, who is said to be in China’s San Francisco consulate.
FBI agents have also interviewed people in 25 US cities who have an “undeclared affiliation” with China’s military.
Prosecutors say it is part of a Chinese plan to send army scientists to the US.
Members of the People’s Liberation Army (PLA) applied for research visas while hiding their “true affiliation” with the military, US justice department attorney John C Demers said in a press release.
“This is another part of the Chinese Communist Party’s plan to take advantage of our open society and exploit academic institutions.”
The arrests come after the US announced a Chinese scientist had taken shelter in the San Francisco consulate, and the day after US officials ordered the closure of China’s mission in Houston, saying it was involved in stealing intellectual property.
On Thursday – before the arrests were announced – Chinese foreign ministry spokesman Wang Wenbin described the US allegations as “malicious slander” and said China “must make a necessary response and safeguard its legitimate rights”.
US President Donald Trump has repeatedly clashed with China in recent months, over trade, the coronavirus pandemic and the new Hong Kong security law.
Hours after the charges were announced US Secretary of State Mike Pompeo denounced a “new tyranny” from China.
Speaking at the Richard Nixon Presidential Library in California, Mr Pompeo called on “on every leader of every nation” to stand up to China, adding that securing freedoms from the Chinese Communist Party was “the mission of our time”.