The U.S. government wants to deport Ali Abdalla to Somalia. The hurdle? The Twin Cities man insists he is an American.

The case hinges on a simple but disputed biographical detail: Abdalla's birth date.

Officially, he was born Jan. 1, a date assigned to thousands of refugees like him from countries where many don't know their birthdays or don't have government records. But his family says his actual birthday was months later, which would mean Abdalla was a minor when his father was naturalized in July 2003 and he automatically became a U.S. citizen, too.

A Twin Cities immigration judge sided with Abdalla in January, dealing a blow to a bid to deport him after a string of criminal convictions. Yet he remains in detention pending an appeal by the government, which questioned the authenticity of a birth certificate the family produced. Abdalla's lawyer is asking a federal judge to intervene.

"His case is emblematic of the government appealing every win and keeping people in custody so it exhausts them," said the attorney, Kim Hunter.

Immigration and Customs Enforcement could not comment on Abdalla's case because of the pending lawsuit. But Jim Stolley, chief counsel at the agency's St. Paul field office, said ICE investigates claims of U.S. citizenship thoroughly.

He said the assigned Jan. 1 birth dates are rarely an issue. But immigrants who have exhausted their legal options to stay have been known to make citizenship claims as a last resort, sometimes backed up by relatives desperate not to see them deported to countries they once fled.

"An alien with a lengthy and serious criminal history is more likely to make a citizenship claim at the 11th hour," he said.

ICE has recently faced scrutiny after a Los Angeles Times report highlighting relatively rare cases in which U.S. citizens spent months in detention while trying to prove they did not belong in the agency's custody.

Abdalla arrived in the United States in 1996 with his family, refugees from Somalia's civil war. He, his parents and siblings were all listed with the same birthday: Jan. 1.

Resettlement and immigration officials have assigned the date to natives of Somalia and other African and Asian countries. In some cases, residents there don't celebrate and track birthdays, or else use traditional calendars. In others, governments did not keep birth records, or refugees lost documents amid upheavals.

The practice can create complications for both immigrants and U.S. authorities, for instance, in figuring out whether newcomers are eligible for public education or Social Security benefits. A 2013 Minnesota Law Review article explored how "the immigrant age problem" can pose challenges in the criminal justice system, where defendants face dramatically lesser sentences if they are tried as juveniles.

The issue also comes up in cases like Abdalla's, involving claims of derivative citizenship granted to those younger than 18 when their parents are naturalized.

Abdalla became a legal permanent resident two years after his arrival. But following an attempted drug sale, disorderly conduct, theft and assault convictions, ICE set out to deport him in 2010. He told an ICE officer he believed he was a U.S. citizen, but the agency and an immigration judge were not convinced.

He was ordered deported at a time when the United States was not sending people back to Somalia. He went on to rack up convictions for violating a domestic protection order, fifth-degree assault and marijuana possession in Minnesota.

As deportations to Somalia resumed, Abdalla was detained by immigration authorities in July. Last fall, the local immigration court agreed to revisit his case. His father, Mohamed Suleyman, testified and provided a sworn affidavit that Abdalla's birthday was not in January but in December 1985, making him 17 at the time Suleyman became a U.S. citizen.

Suleyman told the judge he was sure Abdalla was born in December because the family held a large traditional celebration in honor of his birth, and the Somali economy tanked soon after. He also produced a birth certificate listing Abdalla's birth date as Dec. 24, which he says a relative still living in Mogadishu tracked down years ago.

"In front of God, I just told all the truth," he said in an interview.

Once again, the government was not convinced.

An ICE forensics lab found an alteration to the English version of Abdalla's name on the certificate, though it could not say whether the change was made earlier to fix an error or more recently to tamper with the document. It also noted that Ali Haji Musse, who signed the certificate as mayor of Mogadishu, was not the city's mayor in 1985.

U.S. Citizenship and Immigration Services pointed to that analysis as one reason it denied Abdalla's request for a certificate of citizenship last year. It noted his father had listed only Abdalla's birth year on a resettlement form, leaving the day and month blank. And Abdalla had consistently used the Jan. 1 birth date, the agency said.

Hunter is appealing the decision. For one thing, she said, changing one's official birth date is a tall order, so Abdalla stuck with the date assigned to him.

Immigration Judge Ryan Wood found Abdalla's father credible and noted the forensic analysis of the certificate was inconclusive. This is also a case of simple math, Wood said: Assuming the Jan. 1 birthday was likely arbitrarily assigned, there were 181 days in 2003 before the July 1 naturalization of Abdalla's father and 183 days after, or a 50.14 percent chance Abdalla's birthday came after the ceremony.

Hunter had also submitted as evidence several birth certificates signed around the same time by Ali Haji Musse along with letters from ICE suggesting the agency had provided them to the Somali Embassy to request travel documents for deportees.

"It is difficult to understand how these birth certificates can be deemed reliable for removal, but not for claims of United States citizenship," Wood noted in his order dismissing Abdalla's deportation case.

ICE said birth certificates are used only with extensive other documentation when seeking travel documents for deportees.

The agency is challenging Wood's decision. Hunter asked the federal court in Minneapolis to order Abdalla's release after more than nine months in ICE custody. The government has until May 22 to respond.

Stolley, the St. Paul ICE office's chief counsel, said the agency calls on officials to begin investigating citizenship claims and alert higher-ups in the agency's Washington, D.C., headquarters within 24 hours of receiving such claims.

"No one wants to keep any U.S. citizens in custody, because we have no jurisdiction over them," he said.

Mila Koumpilova • 612-673-4781