Nearly two dozen former detainees at the Guantanamo Bay military prison have disappeared from public view, largely cut off from the outside world since their transfer to a secretive rehabilitation program run by the United Arab Emirates.

The men have had limited contact with their families, some for more than two years, and have not been told when they might be released, according to their relatives, attorneys, and current and former U.S. officials.

Their uncertain fate exposes the limits of the United States’ ability to track and safeguard inmates resettled overseas as part of an effort to close the 9/11-era prison, and highlights the consequences of the Trump administration’s decision to close a State Department office tasked with overseeing Guantanamo matters.

Interviews with attorneys for 19 of the former detainees found that few, if any, of the 23 men transferred to the UAE between 2015 and 2017 have been released, despite what attorneys said were informal assurances that they would be out within about a year.

Reversing course from his predecessor, President Trump has vowed to keep Guantanamo open and barred the overseas resettlement of detainees, whom he has characterized as “extremely dangerous people.”

But the situation of those already released, most of whom have never been charged, remains shrouded in mystery.

One of those men is Haji Wali Mohammed, an Afghan citizen held at Guantanamo for 14 years before he boarded a plane in January 2017 and prepared to begin what his attorney was informed would be a temporary rehabilitation program in the UAE.

Like a well-known program in Saudi Arabia, the more recently established UAE initiative was designed to ensure that prisoners weren’t radicalized and could adapt to outside life.

But after more than 16 months at the UAE-run center, Mohammed has become “very hopeless,” according to his son, Abdul Musawer, who has spoken with his father periodically.

“The U.S. government said my father would be freely living with his family, but they lied,” he said from his home in Afghanistan.

Although some of the men transferred to the UAE report satisfactory conditions and appear to be progressing through a program granting prisoners greater liberties over time, others remain under restrictions and express mounting distress.

According to lawyers and family members, some of the men have not been permitted to use the Internet or go outside. Periodic phone calls to family members are typically limited to five minutes, and are sometimes cut off if the conversation veers into politics or conditions at the center.

In a recent call to his family, Ravil Mingazov, a Russian who was moved to the UAE center in January 2017, suggested that conditions were worse than at Guantanamo, according to his mother, Zukhra Valiulina.

“He said, ‘Mama, this is a prison,’ ” Valiulina said in a phone interview.

Although prisoners at Guantanamo are cloistered at an isolated naval base, the U.S. military has allowed periodic visits by lawyers and the Red Cross, and provided certain information to the media. Not so in the UAE.

The family of another Afghan, named Obaidullah, who was transferred in August 2016, was able to visit him early in his time in the UAE. But subsequently he was out of touch with his family for more than a year, according to attorney Anne Richardson. “This seems like indefinite detention all over again,” she said.

Other attorneys say their former clients have reported satisfactory conditions to their families, possibly because they are in the later stages of the program. Some former detainees have received multiple visits from family members, lawyers said. UAE authorities have provided visas and money for other families.

No matter the conditions, nearly everything about the UAE program remains secret, even its location. Attorneys and relatives of the men say at least some have reportedly been moved to a new site in recent months.

Neither U.S. nor UAE officials responded to requests for information about the former detainees. Generally, the UAE government has discouraged scrutiny of its detention practices at home and abroad.

A State Department spokeswoman said the department hoped the detainees would be integrated into their new countries.

“We remain engaged with host governments to consult on issues that arise,” she said, speaking on the condition of anonymity because she was not authorized to speak publicly.

Attorneys who represented the men while they were in U.S. custody — some over many years — say they have been unable to get even basic information.

In letters this year to the State Department and the UAE’s Foreign Ministry, several lawyers requested the men be visited by their families and the Red Cross. They also asked for a time frame for their release and “clarity on the rights they will have.”

Previous entreaties, they wrote in February 2018, “have either been met with silence or with contradictory instructions.”

Rep. Eliot L. Engel (N.Y.), the top Democrat on the House Foreign Affairs Committee, blamed the Trump administration for shutting down the State Department’s Guantanamo office, which negotiated the transfer agreements and followed up on resettled detainees.

“The U.S. government made commitments to protect our security and the rights of former detainees,” he said in a statement. “On both counts, the administration is utterly failing to meet its responsibilities.”

Attorneys say they were never permitted to see the agreements but were told by the State Department that the men would cycle through the UAE program and gradually be granted greater freedoms, at first inside and then outside the facility.

“We felt that, because this was the established practice, this was great,” said Gary Thompson, who represented Mingazov. Thompson had represented another Guantanamo prisoner who went through the Saudi program before being released.

“However, weeks became months and months became over a year,” Thompson said. “It started to slip away, and then calls to his family became very brief and sounded funny. We just can’t figure out what’s happening.”

In all, 196 inmates were transferred overseas under resettlement agreements negotiated by the Obama administration. Hundreds more were released by the George W. Bush administration.

While many inmates transferred in recent years have adapted to their new homes, others have not. A Syrian man resettled in Uruguay has repeatedly attempted to violate a travel ban. Two former detainees were recently deported from Senegal.

Former officials say the UAE, a close U.S. ally, agreed to take the detainees and establish the rehabilitation center as a favor to President Barack Obama. The president needed a home for detainees, especially Yemenis, who couldn’t be sent back to their country because of deteriorating conditions there.

Officials who worked on the transfers say the extended detention in the UAE violates the spirit of that arrangement.

“It is one thing to put the guys in a rehab program, or otherwise evaluate them for a short period, but this seems like the UAE is imprisoning them on behalf of the U.S. government,” a former official said. “That wasn’t the deal and isn’t right.”

Several former U.S. officials voiced confidence that UAE authorities would make appropriate judgments about the inmates’ readiness to be released. Complicating the issue, some of the men struggle with mental-health issues.

Stephen Vladeck, a professor at the University of Texas School of Law, said U.S. law did not impose any obligations on the government once detainees were no longer in its custody. “Once we cut ties, there really aren’t remedies under U.S. law,” he said.

Thompson said the situation was even more frustrating than Guantanamo. “Before, we could at least file a petition for habeas corpus, we could at least get on a plane and go to Guantanamo. We at least had procedures, even if they were kangaroo procedures,” he said. “This is deeply frustrating because there is no process.”

Julie Tate and Paul Sonne in Washington, Sayed Salahuddin in Kabul, Kareem Fahim in Istanbul and Souad Mekhennet in Frankfurt contributed to this report.