The US State Department has revoked 6,000 student visas since Secretary of State Marco Rubio took office seven months ago, it said Monday.

Rubio, to the delight of President Donald Trump's right-wing base, has proudly moved against students using an obscure law that allows him to rescind visas for people deemed to counter US foreign policy interests.

The Trump administration has also more broadly sought mass deportations of people in the United States illegally.

"The State Department has revoked over 6,000 student visas for overstays and law violations, the vast majority being assault, DUI, burglary and support for terrorism," a State Department official said.

The official said that about 4,000 of the visas were for violations of the law.

The State Department did not break down the visas by nationality. Rubio has vowed to be aggressive in targeting students from China.

The top US diplomat in March told reporters that he was revoking visas daily, saying of activist students: "Every time I find one of these lunatics, I take away their visas."

He has particularly pointed to students who have protested against Israel, and accused activists of anti-Semitism, charges they deny.

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

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.

Khalil, whose son was born while he was in detention, has since sued the Trump administration, saying it sought to "terrorize" him.

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. 

She had been taken away off a Massachusetts street by masked plainclothes agents.

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.