At least 147 international students were abruptly stripped of their ability to stay in the United States in recent days, according to universities and media reports, sowing fear among students and confusion at schools scrambling to help students facing detention and possible deportation.

The moves targeted students at a wide range of universities, from private institutions like Harvard and Stanford to public ones like the University of Texas at Austin and Minnesota State University-Mankato. The University of California had dozens of cases reported across its campuses.

Several immigration lawyers told The New York Times that they began receiving frantic emails and calls late last week from students who had been notified by the State Department or their universities that their visas or statuses had been terminated without clear justifications.

Criminal convictions have always put students at risk of losing their status, but participation in political actions and committing traffic infractions have rarely been cited as justifications.

In some cases, immigration officers have arrested international students related to their involvement in pro-Palestinian causes. In other cases, students had committed legal infractions, such as driving over the speed limit or while intoxicated, often years ago, several immigration lawyers said in interviews.

But lawyers said the Trump administration had often given no reason at all, leaving them to guess why students were targeted.