WASHINGTON, D.C. — All 55 million foreigners who hold visas for the United States are subject to continuous review, the State Department warned Thursday as President Donald Trump ramps up his crackdown on visas and immigration.

"The Department's continuous vetting includes all of the more than 55 million foreigners who currently hold valid US visas," a State Department official said.

"The State Department revokes visas any time there are indications of a potential ineligibility, which includes things like any indicators of overstays, criminal activity, threats to public safety, engaging in any form of terrorist activity or providing support to a terrorist organization."

The official did not say that all 55 million visas were under active review, but made clear that the Trump administration considered all of them fair game.

The official, speaking on customary condition of anonymity, said that the Trump administration was stepping up scrutiny in particular for students.

"We're reviewing all student visas," the official said, saying the State Department was "constantly monitoring what people have said" on social media, which visa applicants are now required to show.

Secretary of State Marco Rubio has proudly targeted anti-Israel protesters, using an obscure law that allows him to rescind visas for people deemed to counter US foreign policy interests.

The State Department earlier said it has revoked 6,000 visas since Rubio took office in January with Trump.

It marks four times as many student visas as president Joe Biden's administration revoked in the same period the previous year, according to the State Department.

Rubio has argued that the administration has the right to issue and revoke visas without judicial review and that non-US citizens do not enjoy the US constitutional right to free speech.

But the administration has faced setbacks in two of the highest-profile cases.

US says all 55 million visas fair game for review

Mahmoud Khalil, a legal permanent resident in the United States who led pro-Palestinian protests at Columbia University, was freed in June by a judge., This news data comes from:http://uehr-ua-coui-vrvo.ycyzqzxyh.com

Rumeysa Ozturk, a Turkish graduate student at Tufts University who wrote a piece in a campus newspaper critical of Israel, was freed by a judge in May pending arguments.