Migrants who entered under two programs — the CBP One application migrants used to schedule appointments to enter the US, and a Biden administration initiative that let in certain migrants fleeing Cuba, Nicaragua, Venezuela and Haiti — could be affected by the memo, which was signed late Thursday by the acting head of the Homeland Security Department.

A Trump spokesperson did not immediately respond to requests for comment.

In Massachusetts, advocates estimate that tens of thousands of people came to the state under these humanitarian provisions, which give temporary permission to stay in the United States. Many of the migrants who have made their way to the state have spent months waiting in Mexico, at migrant shelters or in rented rooms, in cities that are rife with cartel violence and kidnappings.

They do this, many have told the Globe, for an opportunity to enter the US legally, and work in the country with authorization, under the Biden era programs that looked to curb illegal border crossings and offer legal pathways for entry.

But now, some of these migrants could be under threat of being targeted for deportation, particularly if they have yet not applied for another legal status, such as asylum or Temporary Protected status, legal advocates say.

These families, Yountz said, “have followed all of the rules under the previous administration.”

“Trump has said he’s going after murderers and criminals. But in reality, his strategy is quite lazy,” Yountz said. “He’s going after people who followed the rules and are currently in legal parole status because they willingly offered their name and addresses to the federal government.”

Jeffrey Thielman, who runs the Boston resettlement agency International Institute of New England, served 16,000 people with humanitarian parole status in 2024 alone. This large class of immigrants include many families that fled desperate conditions or war in their home countries.

On Friday, he told his staff to “keep your heads down” and continue to help connect clients with federal benefits, English classes, and to coordinate apartment searches. His staff also work to enroll children in schools, sign families up for medical insurance, and prepare people for job interviews, among other things.

“It’s unethical and immoral that the United States of America allowed people into this country for humanitarian purposes and is now turning their backs on them,” he said. “It’s fundamentally wrong. This is not the way the rule of law should work.”

Humanitarian parole has been used as a legal tool for decades, allowing people admission to the country who were unable to use other pathways because of political and economic strife or their home country’s poor relations with the United States. Under the Biden administration, half a million Cubans, Haitian, Nicaraguans and Venezuelans were welcomed as part of the program, which allowed migrants to live and work lawfully for two years while they applied for longer-term status.

The move to undo the protection, which was first reported by the New York Times, is one of a flurry of actions the Trump administration has taken in recent days to follow through on his campaign promises of cracking down on immigration.

Yountz, the immigration attorney, said while there are thousands of immigrants in Massachusetts under these humanitarian provisions, most have either applied for, or received, Temporary Protected Status or asylum, which would seem to offer a layer of protection of deportation under this memo, Yountz said.

It does not mean that these residents “are going to fall into undocumented status,” Yountz said.

“This is not a wholesale revocation of parole,” Yountz said.

But those who have not applied for other kinds of status and are just here under parole appear to be particularly vulnerable.

“We are concerned. There is a vagueness to this memo, and many of Trump’s orders, that make it unclear who will, or will not be, swept up,” she said.

Regardless, Pastor Dieufort Fleurissaint, better known as Pastor Keke, a prominent advocate in Greater Boston’s Haitian American community, called this a “heart-wrenching situation.”

He has been receiving a flurry of calls since Monday, when the Trump administration released a stream of executive orders, many of them immigration-related, from concerned Haitians in Massachusetts asking how they would be affected by the new rules.

Since many were in the country legally under humanitarian provisions, Pastor Keke tried to assuage their fears, assuring them they would likely be safe. But when he saw the news of the internal memo last night, his heart sank.

“I’m very worried, because they [ICE] already know where these people are located,” he said. “This is the reality, and we have to face it.”

Already, he has heard that some migrants are avoiding their English classes, health appointments, and staying home because they’re panicked.

“That news last night will heighten the tension,” he said. “Now, even people with humanitarian provisions are not immune from deportation . . . this is a very, very critical situation.”

Giulia McDonnell Nieto del Rio can be reached at giulia.mcdnr@globe.com. Follow her @giuliamcdnr. Samantha J. Gross can be reached at samantha.gross@globe.com. Follow her @samanthajgross.