The US State Department has instructed all US consulates abroad to begin additional screening of those who have applied for visas to go to Harvard University, for any reason, according to a diplomatic cable obtained by Reuters today. It is another action that expands President Donald Trump’s crackdown on the university.

In a cable dated today and sent to all US diplomatic and consular authorities, US Secretary of State Marco Rubio instructs that “additional screening” of individuals who have applied for “non-immigrant visas” and “wish to travel to Harvard University for any purpose” should begin immediately.

Such applications may have been submitted by prospective students, individuals already studying at the university, employees, contractors, guest speakers, and even tourists.

Harvard University has failed to maintain “a campus environment free of violence and anti-Semitism,” the cable claims, noting that the increased screening measures are aimed at helping consular officers identify visa applicants who have a “history of anti-Semitic harassment and violence.”

In the past, the US has required additional screening of people from certain countries. Applying such procedures against Harvard appears to be an unprecedented use of the visa process against a university that has fallen into disrepute.

According to the cable, consular officials should consider the possibility of questioning the credibility of the applicant if his or her social media accounts are not public. “If you are not fully convinced that the applicant, while in the U.S., will engage in activities consistent with his or her nonimmigrant visa status, you should deny the visa,” the document adds.

In recent times Rubio has said that he has revoked the visas of hundreds, possibly thousands of people – including students – for engaging in activities that run counter to U.S. foreign policy priorities.

“If you come here to cause trouble, you’re probably going to have trouble,” Rubio told reporters on April 7.