White House: Rubio reserves the right to revoke green card or visa of anti-Israel activist Mahmoud Khalil

Leavitt said that under the Immigration and Nationality Act, the secretary of state has the right to revoke a green card or a visa for individuals who are "adversarial to the foreign policy and national security interests of the United States of America." 

"And Mahmoud Khalil was an individual who was given the privilege of coming to this country to study at one of our nation's finest universities and colleges, and he took advantage of that opportunity, of that privilege, by siding with terrorists, Hamas terrorists, who have killed innocent men, women and children," Leavitt said at the White House press briefing. "This is an individual who organized group protests that not only disrupted college campus classes and harassed Jewish American students and made them feel unsafe on their own college campus, but also distributed pro-Hamas propaganda fliers with the logo of Hamas. That is the behavior and activity that this individual engaged in."

Leavitt said the Department of Homeland Security provided her with those fliers, which she says were distributed with the help of Khalil on the Columbia University campus and are now on her desk.

She said she considered bringing them to the briefing but decided against it because she "didn't think it was worth the dignity of this room to bring that pro-Hamas propaganda." 

The official said Section 237 of the Immigration and Nationality Act broadly contains grounds for which an alien who is in the U.S. after having been admitted or having had his or her status adjusted to that of lawful permanent resident may be removed. 

The senior State Department official stressed this is about national security, not free speech. 

Khalil, who was a graduate student at Columbia until December, was taken into custody Saturday by Immigration and Customs Enforcement (ICE) at his university-owned apartment in New York and transported to a detention center in Louisiana. 

Khalil was born in Syria to Palestinian parents and entered the U.S. to attend Columbia in 2022. He subsequently got married to an American citizen, who is now eight months pregnant, according to the Associated Press.

New York City Mayor Eric Adams was asked at his own media availability earlier Tuesday about Khalil's "due process," but the Democrat said he wishes his own due process was considered when the Biden Justice Department brought a corruption case against him. "What I'm finding surprising is the level of support you're all displaying. But I didn't see that support for me," Adams told reporters. "Even after we saw the emails and text messages that there's a potential [that] this is politically motivated." 

A federal judge in New York City on Monday blocked Khalil's deportation. A hearing is set for Wednesday to weigh motions from his lawyers claiming ICE violated his constitutional rights and asking for him to be moved back to New York. 

Trump applauded Khalil's apprehension, saying it is "the first arrest of many to come," while some Democrats are criticizing the move. "We know there are more students at Columbia and other Universities across the Country who have engaged in pro-terrorist, anti-Semitic, anti-American activity," Trump wrote on Truth Social. "We will find, apprehend, and deport these terrorist sympathizers from our country - never to return again."

Democrats on the Senate Judiciary Committee, led by Sen. Dick Durbin, D-Ill., the second-highest ranking Democrat in the chamber, called Khalil's detention "straight-up authoritarianism." 

Hundreds of protesters demonstrated in New York City on Monday night demanding Khalil's release and calling for a nationwide walkout of classes is set for noon Tuesday to protest what they deem "genocide" against the Palestinian people and the Trump administration's plan to cut federal funding to colleges that permit "illegal" protests. 

That student walkout failed to materialize as of early Tuesday afternoon, but a small group of protesters were seen on the steps of Columbia's campus chanting in favor of Khalil's release. 

The Associated Press contributed to this report.