Washington, DC - Rights groups are calling for the release of an Afghan man with a special visa given to those who assist the United States military overseas who has been held by immigration authorities for nearly three weeks.

Abdul, whose full name is not being revealed for security reasons, arrived at the Newark, New Jersey airport on March 13 as part of the Special Immigrant Visa (SIV) programme. Afghans who are in life-threatening danger are eligible for this status.

"Border agents coerced him into signing away his fundamental rights, even though the federal government understood his life was in danger in Afghanistan because of his service to the United States," Jeanne LoCicero, a lawyer with the American Civil Liberties Union, said in a statement.

The man and his family had previously been attacked by the Taliban armed group. US immigration authorities are trying to deport him.

Abdul, who holds a sponsorship letter from a retired US Army sergeant, worked as a cashier for five years at a cafeteria next to the US embassy in Afghanistan's capital Kabul until February, shortly before he departed for the United States.

Instead of a warm welcome, Abdul was detained on arrival.

"If they had stamped his passport, he would be a lawful US resident," Jason Scott Camilo, an immigration lawyer representing Abdul, told Al Jazeera.

Camilo said the Afghan was initially interrogated for 28 hours by agents from the Customs and Border Protection (CBP) and Immigration and Customs (ICE) agencies.

The lawyer said Abdul was without legal counsel for more than a day. He was held in "a big waiting room. There's a couple of jail-like cells without beds … He couldn't sleep," Camilo said.

Shortly before his scheduled deportation, the International Refugee Assistance Project (IRAP) filed a case on Abdul's behalf, which was denied. It then filed an emergency appeal and a court placed a temporary stay on his deportation pending a review of his case.

Abdul has since passed an initial interview for refugee status and is awaiting a court review in mid-April. However, he remains locked up in the Elizabeth Detention Center, a private facility contracted by ICE.

Betsy Fisher, IRAP's policy director, said Abdul's detention is part of a larger clampdown on the Special Immigrant Visa programme.

In December 2016, then-president Barack Obama signed the National Defense Authorization Act, which only allocated 1,500 more SIV visas. With so few visas available, Fisher explained, interviews for applicants at the US embassy in Kabul ended on March 1.

"There are roughly 10,000 people still waiting for SIVs," Fisher told Al Jazeera. "The fact that applicants are now in indefinite limbo because Congress has failed to provide the number of visas we knew were needed is a disgrace and abandonment of our allies."

Abdul is the second Afghan SIV recipient to be detained this month. On March 4, a family of five that had been granted approval to move to the US because of their father's work was detained in Los Angeles.

Al Jazeera contacted ICE and CBP for comment, but did not immediately receive a response.

Follow Creede Newton on Twitter: @creedenewton