RYAN J. FOLEY Groups that provide legal services to immigrants filed a lawsuit Wednesday seeking to stop the Trump administration’s new policy of hiding the locations of tens of thousands of detainees with final deportation orders.

The policy, adopted suddenly last month to expedite deportations, interferes with immigration lawyers’ rights by making it difficult, and sometimes impossible, to locate their clients, according to the lawsuit filed in federal court in Boston. It asks a judge to issue an order blocking the “unlawful and inhumane” change.

“No one should be denied a meaningful opportunity to defend their rights because the government has made it impossible for their lawyer to find them,” said Jacquelynne Bowman, executive director of Greater Boston Legal Services, one of the four groups listed as plaintiffs. “This arbitrary new administrative change leaves hundreds of thousands of people at risk of potentially life-altering consequences without essential legal help.”The lawsuit challenges U.S. Immigration and Customs Enforcement’s decision, first reported by The Associated Press, to remove the locations of people facing final removal orders from its Online Detainee Locator System and to instruct staff not to reveal their whereabouts. As of last month, the move affected more than 16,000 of the nearly 69,000 detainees who were in ICE custody.

ICE and its parent agency, the Department of Homeland Security, didn’t immediately respond to a message seeking comment on the lawsuit.

The agencies have not publicly confirmed the change, but have said they are prioritizing people with final removal orders for deportation. They have also said they are facing a “historic number of injunctions” from courts blocking their efforts. The agencies have denied that they are disappearing detainees , saying they remain free to make phone calls.

Since 2010, lawyers and family members have used the online system to track detainees as they get moved from facility to facility through ICE’s sprawling detention network .

Approximately 1.4 million people living in the U.S. are subject to final orders of removal, which means an immigration judge has ruled they should be deported and the decision has been upheld on appeal or not appealed.

Those individuals still have several options to challenge the conditions of their detention and looming deportations, including asking to reopen proceedings, seeking relief from removal to third countries and challenging violations of their rights. Federal judges have ruled thousands of times that detainees should be released or granted bond hearings.

Since the change went into effect, lawyers have been unable to find clients and potential clients and have spent “significantly more time” tracking down others, the lawsuit says. Calls to ICE, including to its Detention and Removal Information Line, “lead to long wait times on hold, sudden hang-ups, a general lack of information or no answer at all,” it says.

As a workaround, some lawyers have tried to find their clients through an ICE program that schedules legal calls, but only a small percentage of detention centers use it, the lawsuit says. The result has been delayed or missed legal filings and fewer cases taken, according to the organizations.

The lawsuit argues the change violates the Administrative Procedure Act because it was adopted without explanation and the First Amendment, which protects lawyers’ ability to advise people of their legal rights and seek prospective clients.