As immigrants arrived at Faneuil Hall in Boston for their naturalization ceremony on Thursday, some were told by federal authorities that they could not proceed due to their countries of origin, a development first reported by GBH.

The naturalization ceremony, which is the final step in obtaining U.S. citizenship, requires approved applicants to take the Oath of Allegiance and receive their Certificate of Naturalization, according to the U.S. Citizenship and Immigration Services (USCIS).

However, some approved individuals were stopped by USCIS officials upon arrival at Faneuil Hall, according to GBH.

“One of our clients said that she had gone to her oath ceremony because she hadn’t received the cancellation notice in time,” Gail Breslow, executive director of Project Citizenship told GBH. “She showed up as scheduled, and when she arrived, officers were asking everyone what country they were from, and if they said a certain country, they were told to step out of line and that their oath ceremonies were canceled.”

The client is a Haitian woman in her 50s who had a green card since the early 2000s and began working with Project Citizenship in January, the media outlet reported.

The abrupt halt is a direct result of a new order from the Trump administration that mandates an immediate pause on all immigration applications filed by people from 19 countries that they consider “high risk” for national security.

“People are devastated and they’re frightened,” Breslow told GBH News. “People were plucked out of line. They didn’t cancel the whole ceremony.”

To whom does the immigration pause apply?

The freeze applies to a broad range of benefits, including applications for green cards and naturalization, for nationals of the following countries:

AfghanistanMyanmar (Burma)ChadRepublic of the CongoEquatorial GuineaEritreaHaitiIranLibyaSomaliaSudanYemenBurundiCubaLaosSierra LeoneTogoTurkmenistanVenezuela

The new policy will allow the USCIS to reexamine green-card holders who are already residing in the U.S. as it reviews cases that were done under the Biden administration and indefinitely pauses asylum decisions.

“We’re going back on all of these folks that have applied for asylum, people that would be traveling to this country, and looking at more information, what … social media platforms they may have visited, the communications that they have, biometric information and data that we can collect from them, but also from their government, too,” U.S. Homeland Security Secretary Kristi Noem told CNN’s Kaitlan Collins on Monday.

USCIS cited the shooting of two National Guard troops by a suspect who is an Afghan national as a reason for the new policy.

One National Guard member, Sarah Beckstrom, 20, died from her injuries, while another, Andrew Wolfe, 24, was critically injured but is “slowly healing,” and is expected to be in acute care for the next two to three weeks, the BBC reported.

“In light of identified concerns and the threat to the American people, USCIS has determined that a comprehensive re-review, potential interview, and re-interview of all aliens from high-risk countries of concern who entered the United States on or after January 20, 2021 is necessary,” a statement shared on Dec. 2 reads. “Lastly, USCIS may, when appropriate, extend this review and re-interview process to aliens who entered the United States outside of this timeframe.”

The hold will remain in place until USCIS Director Joseph Edlow decides to lift it, the memo states. The agency has given itself 90 days to create a prioritized list of cases for review and potential referral to immigration enforcement or other law enforcement agencies.