…Eligible recruits are required to have legal status in the U.S., such as a student visa, before enlisting. More than 5,000 immigrants were recruited into the program in 2016, and an estimated 10,000 are currently serving. Most go the Army, but some also go to the other military branches.

To become citizens, the service members need an honorable service designation, which can come after even just a few days at boot camp. But the recently discharged service members have had their basic training delayed, so they can’t be naturalized.

Margaret Stock, an Alaska-based immigration attorney and a retired Army Reserve lieutenant colonel who helped create the immigrant recruitment program, said she’s been inundated over the past several days by recruits who have been abruptly discharged.

All had signed enlistment contracts and taken an Army oath, Stock said. Many were reservists who had been attending unit drills, receiving pay and undergoing training, while others had been in a “delayed entry” program, she said.

“Immigrants have been serving in the Army since 1775,” Stock said. “We wouldn’t have won the revolution without immigrants. And we’re not going to win the global war on terrorism today without immigrants.”

…The AP interviewed Calixto and recruits from Pakistan and Iran, all of whom said they were devastated by their unexpected discharges.

“Now the great feeling I had when I enlisted is going down the drain,” said Calixto, 28. “I don’t understand why this is happening.”

In hopes of undoing the discharge, he filed a lawsuit in Washington, D.C., last week alleging the Defense Department hadn’t given him a chance to defend himself or appeal. He said he was given no specific grounds other than “personnel security.”

Calixto, who lives in Massachusetts and came to the U.S. when he was 12, said in an email interview arranged through his attorney that he joined the Army out of patriotism.

In the suit, Calixto said he learned he was being kicked out soon after he was promoted to private second class.

The Pakistani service member who spoke to the AP said he learned in a phone call a few weeks ago that his military career was over.

“There were so many tears in my eyes that my hands couldn’t move fast enough to wipe them away,” he said. “I was devastated, because I love the U.S. and was so honored to be able to serve this great country.”

He asked that his name be withheld because he fears he might be forced to return to Pakistan, where he could face danger as a former U.S. Army enlistee.

Portions of the 22-year-old’s military file reviewed by the AP said he was so deeply loyal to the U.S. that his relationships with his family and fiancee in Pakistan would not make him a security threat. Nonetheless, the documents show the Army cited those foreign ties as a concern.

…Non-U.S. citizens have served in the military since the Revolutionary War, when Continental soldiers included Irish, French and Germans. The U.S. recruited Filipino nationals to serve in the Navy in the 1940s, and worked to enlist Eastern Europeans in the military over the next decade, according to the Defense Department.

Since Sept. 11, 2001, nearly 110,000 members of the Armed Forces have gained citizenship by serving in the U.S. military, according to the Defense Department.

Many service members recruited through the program have proven to be exemplary. In 2012, then-Sgt. Saral K. Shrestha, originally from Nepal, was named U.S. Army Soldier of the Year.

In general, the immigrant recruits have been more cost-effective, outperforming their fellow soldiers in the areas of attrition, performance, education and promotions, according to a recently released review by the RAND Corporation, a nonprofit research institution.