The State Department has halted the scheduling of new visa interviews for foreign students hoping to study in the U.S. while it prepares to expand the screening of their activity on social media, officials said.

A U.S. official said Tuesday the suspension is intended to be temporary and does not apply to applicants who already had scheduled their visa interviews. The official spoke on condition of anonymity to discuss an internal administration document.

A cable signed by Secretary of State Marco Rubio and obtained by The Associated Press says the State Department plans to issue guidance on expanded social media vetting.

“Effective immediately, in preparation for an expansion of required social media screening and vetting, consulate sections should not add any additional student or exchange visitor visa appointment capacity” until the guidance is issued, the cable says.

Asked about the suspension at a briefing Tuesday, State Department spokesperson Tammy Bruce said the U.S. uses every available resource to vet people applying for visas.