President Donald Trump's administration has issued a memo for universities that seeks to restrict issuance of certain internship work authorisations for international students as the federal government warned that colleges not complying with the regulations may lose certification to enroll foreign students.

The federal memo dated 24 August said the Student and Exchange Visitor Program, which is part of the US Immigration and Customs Enforcement agency, has "observed a rise in Curricular Practical Training (CPT) authorisations that appear to violate regulatory requirements which permit CPT only where the training is an integral part of an established curriculum."

"Failure to comply with SEVP regulations may result in an institution losing certification to enroll foreign students," the memo said.

It resulted in some schools, including the University of California, Los Angeles and the University of California, Berkeley, pausing certain applications for work authorisations for international students.

"UCLA has paused certain Curricular Practical Training authorizations while it reviews recent federal guidance and determines next steps," a UCLA spokesperson said.

UC Berkeley's international office said the 24 August memo was "more narrow in focus, more direct, and includes content that is more restrictive in nature." The federal government had also issued an earlier memo in mid-August.

UC Berkeley's international office said it is unlikely that it will process certain work authorisation applications "in the near future" and urged those international students to plan accordingly.

It said it will continue processing "degree-requirement" CPT as normal and would resume processing "Doctoral Dissertation and Master's Thesis Research CPT." The office said it would consult legal experts to develop new processes aligning with new federal requirements.

"Nothing about these regulations has changed," the Department of Homeland Security, ICE's parent, said in a statement. "However, schools and employers should consider themselves on notice: under President Trump, abuse of this generous system will no longer be tolerated."

Trump has targeted universities with probes and funding threats over issues like pro-Palestinian protests against US ally Israel's assault on Gaza, diversity initiatives, climate programs and transgender policies. Rights advocates have raised free speech, academic freedom and due process concerns.

Separately, the US Justice Department alleged on Thursday admissions practices at the George Washington University School of Medicine and Health Services favored Black and Hispanic applicants, citing findings of a probe as the Trump administration continued its diversity crackdown.