Federal agents in Massachusetts have halted the controversial practice of arresting undocumented immigrants who are visiting government offices in hopes of gaining legal status, an immigration official told a federal judge Tuesday.

The decision represents a reversal by US Immigration and Customs Enforcement and follows sharp questioning by a federal judge in Boston over the practice, which has drawn a legal challenge from the American Civil Liberties Union as a symbol of the Trump administration’s aggressive stance on illegal immigration.

In a tense court hearing Tuesday, Thomas Brophy, the acting director of Boston’s ICE field office, told US District Court Judge Mark L. Wolf that he ordered an end to the arrests on Feb. 16 after learning that immigrants seeking legal status after marrying US citizens had been arrested during scheduled visits to United States Citizenship and Immigration Services offices.

Brophy said he told his officers “we were going to focus on public safety. We were not going to conduct those arrests [at government offices] unless there was a threat to national security or public safety.’’

Brophy said that the practice had occurred under his predecessor, and he changed it when he took over the job in February. It was unclear Tuesday if the new approach represents a change nationally, or only in Massachusetts. An ICE spokesman declined to clarify it.

As recently as March, ICE had publicly defended the practice as a strategy to keep officers safe while they conducted arrests of immigrants with longstanding deportation orders. In January alone, ICE arrested seven people at immigration offices in Massachusetts and Rhode Island, often immediately after they completed interviews as part of their bid to become legal residents.

“It has always been the case that an arrest could happen at USCIS offices,’’ a spokesman said in March, following the arrest of Lilian Calderon, a Guatemalan mother of two who was arrested by ICE on Jan. 17 at a government office in Rhode Island she and her American husband had visited to answer questions about her marriage.

Calderon was arrested after government officials told her they believed her marriage was legitimate and she could begin the process of applying for legal status through her spouse. She was held for nearly a month at the Suffolk County jail.

She and her husband are among five couples who have sued the Trump administration and the Department of Homeland Security over the arrests. Lawyers for the ACLU and the law firm, WilmerHale in Boston, representing the couples have asked Wolf to let the immigrants stay in the United States with their families as the government considers their applications for lawful status.

Brophy, the local ICE official, said he has heard of no other arrests at government offices in Massachusetts since he issued the order.

Matt Segal, legal director at ACLU of Massachusetts, said he remains concerned about the agency’s aggressive tactics.

“We will keep searching for the whole truth about what was done to our clients, and we will keep fighting for court-ordered relief to protect them, and others like them, from unlawful actions by ICE,’’ Segal said. “Nothing we heard today reduces the need for that relief.’’

Brophy was the first of six ICE employees called to testify Tuesday before Wolf, who ordered the officials to appear in court to answer questions about the arrests of Calderon and at least three other immigrants who had been checking in with the government as they sought legal status.

ICE has said it has the authority to detain anyone with a final removal order for at least 90 days and deport them, but immigrant attorneys have said the detentions violated the immigrants’ rights.

Wolf recently ruled that ICE broke its own rules when the agency decided to extend the detention of two immigrants in custody without giving them proper notice to contest it.

On Tuesday, Wolf questioned ICE officials about the arrest of Lucimar de Souza, a Brazilian immigrant married to an American who was separated from her three children for three months after she was detained at a government office in downtown Boston. She was released on May 8.

Wolf asked why ICE decided to keep her and another Brazilian immigrant, the father of two boys in Connecticut, in custody after Brophy realized they had not been given the required 30-day notice.

Brophy said he thought the solution would be to schedule another review with the proper notice. Even though that would mean keeping them locked up another month? Wolf asked.

“I guess so,’’ Brophy replied.

Brophy, said that he brought in ICE officials to train his staff on detention regulations after he learned of the violations.

During one dramatic moment in the hearing, Wolf played a video filmed the day de Souza was reunited with her 10-year-old son, an American citizen. Brophy watched without expression as de Souza’s son cried in happiness at the sight of his mother.

“Do you see when you look at that video of Ms. de Souza being reunited with her son, that when the government breaks the law it can have profound human consequences?’’ Wolf asked.

“I do,’’ Brophy said. Wolf asked Brophy if he had children.

“Three,’’ he replied.

“Do you think about what it would feel like to be facing the threat of deportation and be separated from your spouse and children for six weeks, five weeks, four weeks?’’ Wolf asked.

“I don’t know if I’ve thought about that, but I understand,’’ Brophy said.

Sitting nearby, de Souza and Calderon fought back tears as the video played.

“Now he knows my emotions,’’ de Souza said during a break in the hearing. “He has [kids]. That was my kid.’’

Wolf, who was nominated by President Ronald Reagan in 1985, is perhaps best known for the 10-month hearing he held in 1998 on the failure of the FBI to tell the US attorney’s office that James “Whitey’’ Bulger and Stephen “The Rifleman’’ Flemmi were working as informants for the agency.

Tuesday’s hearing was highly anticipated by immigrant attorneys who have been railing against ICE tactics. Some who came to watch were gleeful at Wolf’s questioning.

“This is the best television ever,’’ one of them whispered.

The hearing is expected to continue on Wednesday.

Maria Cramer can be reached at mcramer@globe.com. Follow her on Twitter @globemcramer.