The Trump administration has ordered US diplomatic missions worldwide to suspend scheduling new appointments for student and exchange visitor visa applicants, as the State Department prepares to implement expanded social media vetting measures, an internal cable obtained by Reuters revealed on Tuesday.

The directive, issued by US Secretary of State Marco Rubio, instructs consular sections to halt booking new visa interviews for F, M, and J visa categories, pending the completion of a review on the screening process. Already scheduled appointments will continue under existing guidelines, but all available future slots have been withdrawn.

"The Department is conducting a review of existing operations and processes for screening and vetting of student and exchange visitor visa applicants," the cable stated, adding that updated guidance on social media vetting is expected soon.

A senior State Department official confirmed the cable’s authenticity but declined further comment. Meanwhile, State Department spokesperson Tammy Bruce affirmed that the US government will "use every tool" to vet those seeking entry, including students, amid heightened security concerns.

The move is part of the administration’s broader agenda aimed at tightening immigration controls, which has included increased deportations and revocation of visas, particularly targeting individuals perceived to challenge US foreign policy.

The expanded vetting will require consular offices to adjust their procedures and resource allocations, prioritising services for US citizens, immigrant visas, and fraud prevention, according to the cable.

The announcement has sparked protests on American university campuses. Hundreds of Harvard students and faculty gathered on Tuesday to voice support for foreign students and oppose the administration’s actions, including attempts to cut federal funding to the prestigious institution. Harvard, which hosts roughly 6,800 international students — about 27 per cent of its total enrolment — has been a particular focus of the administration’s scrutiny.

Critics argue that the administration’s policies infringe upon free speech rights protected by the First Amendment, especially after reports emerged that student visa holders and green card holders faced deportation for publicly supporting Palestinians or criticising Israeli actions in Gaza.

One high-profile case involves a Turkish student at Tufts University who was detained for over six weeks after co-authoring an opinion piece critical of her university’s response to the Gaza conflict. She was eventually released on bail following a federal court order.

Last week, the administration moved to revoke Harvard’s eligibility to enrol international students, further escalating tensions between the government and academic institutions resisting federal pressure.