In a briefing at the state department, Bruce declined to provide numbers for how many Chinese students would be affected by a new plan to “aggressively” revoke visas announced on Wednesday, but said officials would scrutinise anyone “deemed to be a threat to the country or a problem.”

She declined to detail how those who pose a threat would be determined.

Secretary of state Marco Rubio, announcing the new crackdown, said it would target students including those with connections to the Chinese Communist Party (CCP) or studying in critical fields.

“When it comes to keeping America safe, the US, I further can say here, will not tolerate the CCP’s exploitation of US universities or theft of US research intellectual property or technologies to grow its military power, conduct intelligence collection or repress voices of opposition,” Bruce said.

The announcement on Chinese student visa holders came after the Trump administration ordered its missions all over the world to stop scheduling new appointments for student and exchange visitor visa applicants.

Asked when appointments would come back online, Bruce did not say but recommended that applicants continue checking the US visa system for new appointments.