A half-dozen Maryland Congress members Monday were denied access to a federal immigration field office used to temporarily hold people facing deportation, and where detainee conditions are being challenged in a lawsuit.

Democratic Sens. Angela Alsobrooks and Chris Van Hollen and Reps. Kweisi Mfume, Glenn Ivey, Sarah Elfreth and Johnny Olszewski Jr. gained access to the sixth floor of the George H. Fallon Federal Building, home of the Baltimore field office of U.S. Immigration and Customs Enforcement.

But they weren’t allowed any farther.

The field office’s acting director, Nikita Baker, came out into the hallway and denied them a tour based on a directive she’d been given from “headquarters,” she said.

Mfume, of Baltimore, told Baker they were there to exercise their oversight authority. Van Hollen read her the federal law that says the Department of Homeland Security cannot use any funds to keep members of Congress from entering buildings used to house or detain undocumented people.

Baker nodded and listened. But she didn’t let them in. Undocumented people were being held there temporarily until being moved to long-term detention facilities, she said. But this one was not a “detention center.”

This prompted Alsobrooks to ask “What would you call a place where you were being detained?”

She added: “People here must be deeply ashamed, they don’t want anyone to see it.”

Mfume told Baker they have the right to enter “every facility and every building,” holding immigrants regardless of what its called.

“Your refusal of allowing us to gain entry is a violation of federal law,” said Mfume, a member of the House Oversight and Government Reform Committee.

But Baker held firm during the calm and measured conversation and did not give an answer as to why they couldn’t enter. The Baltimore field office did not immediately respond to a request for comment.

Mfume said he’ll speak to Attorney General Anthony Brown about possible next steps and to the Republican chair of the oversight committee to ensure congressional access to detention facilities across the country.

After news of their visit broke, Maryland’s lone Republican Congressman Andy Harris criticized his colleagues on social media, describing a photo of them sitting in front of the field office’s doors as “stunts for cameras to keep illegals in Maryland.”

The Congress members notified ICE last week they’d planned to visit the Baltimore office. Democratic lawmakers across the country have asserted their oversight authority over an increasingly opaque deportation process.

The Baltimore field office recently held a pastor ripped from his Eastern Shore community and is where Kilmar Abrego Garcia was held before being shipped to a prison in El Salvador.

Elfreth said their offices have heard from constituents who have been detained there who still have not gotten all of their belongings back.

The delegation visit comes months after staffers from Alsobrooks’ and Van Hollen’s offices entered the Baltimore field office in March and found what they said were immigrants being detained in inadequate, overcrowded accommodations, with limited access to food, medicine and bedding.

Democrats in the minority in Congress are using what little power they have to assert their profound disapproval of the Trump administration’s mass deportation efforts.

In May, law enforcement arrested and charged two New Jersey Democrats visiting an ICE detention facility. Newark Mayor Ras Baraka was denied entry, according to court documents. Trespassing charges made against him were later dropped.

Congresswoman LaMonica McIver was charged with assaulting an officer and for interfering when officials asked Baraka to leave. She has pleaded not guilty.

Department of Homeland Security Secretary Kristi Noem told members of Congress they’re required to give 72 hours advance notice before visiting an ICE field office, according to a memo. Maryland delegation members sent Noem a letter last week.

Earlier this year, Maryland’s senators demanded Noem answer questions about the conditions in the ICE holding rooms.

Noem blamed Maryland’s lack of an ICE detention center for the long wait times and the conditions endured by detainees.

In May, two immigrant rights groups filed a federal class action lawsuit against ICE on behalf of two women formerly detained in the Baltimore facility, in what the groups described as “inhumane” conditions.

The women, who were in the country legally, were detained after routine ICE check-ins, according to the case, and kept in the Baltimore holding room for more than 36 hours. The women had limited access to food, water, showers, mattresses, prescribed medications and their attorneys.

Maryland Attorney General Anthony Brown backed the case. In a friend-of-the-court brief filed in June, he wrote that “no individual should be subjected to conditions that deny them basic human dignity” and urged the court to limit detention times.

The federal judge in the case, Julie Rubin, has not issued a final ruling, but has prohibited the federal government from deporting the women while they challenge the legality of their confinement. On Friday, Rubin denied the women’s request to extend that injunction to all others held in the Baltimore hold room currently or in the future.

Baltimore Banner reporter Danny Zawodny contributed to this article.