Advocates for those stripped of their passports believe the process raises serious constitutional concerns.

“They’re being conducted in violation of federal regulations and citizens’ due process rights,” said Ahilan Arulanantham, deputy legal director at the American Civil Liberties Union of Southern California. Consular officials “cannot take your passport without granting you a hearing," he said. “When they take away a citizen’s passport and don’t inform them that they have the right to return (to the U.S.), that is a grave violation of a very basic protection.”

Growing up in Oakland, Hussein lived a life typical of many young immigrants. He kept connected to family in Yemen, yet he became integrated into American life. Winning the district soccer championship for Willard Middle School “for the first time in 30 years,” he said, remains among his fondest childhood memories.

As a political-science major at nearby San Francisco State University, he continued his Yemen trips. On a 2005 visit, he married a Yemeni-American woman with U.S. citizenship. He returned alone to San Francisco, and after graduation he worked in his family’s grocery store and drove a cab. He says he wanted nothing more than to earn enough money to settle his wife and son in Oakland, where he could give them the kind of life his father had given him.

In 2012, Hussein flew to Yemen to take his family home. “I was excited,” he said. “I didn’t expect to be in Yemen any longer than a couple of months.”

But Yemen had, in the decades since Hussein immigrated to the U.S., had become a growing security concern for the U.S. The bombing of the U.S.S. Cole in Aden harbor in 2000 started the trend, and in the wake of the 9/11 attacks, the birthplace of Osama bin Laden’s father became another theater of Washington’s war with Al-Qaeda. The foiled Christmas day underwear bombing attempt on a Detroit-bound airliner and other failed attacks were believed to originate with the Yemen-based Al-Qaeda in the Arabian Peninsula, and the country became the target of a sustained campaign of drone attacks that have killed hundreds of fighters and civilians.

So it was into the walled and heavily guarded U.S. embassy in Sana’a that Hussein walked with his family in 2012 to apply for his son’s passport. Once inside, embassy employees separated Hussein from his family and took him to a small, windowless room, where he said an investigative officer with the State Department accused him of identity fraud. Hussein had a different name, the officer said, and demanded that he reveal it. Many Yemenis have a patronymic, tribal or geographic name that identifies their origin, which is often shortened for convenience when immigrating to the U.S. That’s what embassy officials used to claim fraud was committed.

Unless he signed a form, Hussein recalled the officer telling him, he would be imprisoned, his U.S. passport would be confiscated, and his son’s application would be denied.

After a lengthy interrogation about the names of his parents, siblings and their tribe, Hussein signed the form saying he had obtained his U.S. passport using a false identity. “After being in there for hours, I gave in. I didn’t realize what it would lead to,” he told Al Jazeera by phone from Yemen.

The moment Hussein signed the statement, he said, the officer seized his passport and told him to leave the embassy. The State Department’s internal guidelines, provided to Al Jazeera by the official, stipulate that an individual must be issued a temporary passport if a case is forwarded to the United States Citizenship and Immigration Services (USCIS): “While the appropriate review is taking place, the applicant should be issued a limited one-year validity passport … or a three-month limited emergency photodigitization passport.”

Hussein said he doesn’t know if his case is up for review. He sent numerous emails to the Sana’a embassy in the month after his was confiscated, asking what he should do. He said the embassy responded with an unsigned email stating that the basis for the revocation was the sworn statement in which he admitted that he had obtained his passport under a fraudulent identity. He has received no answer to his question about how to challenge the decision. Al Jazeera’s emails and calls to the embassy in Sana’a have gone unanswered.

“There are no words to describe my frustration,” said Hussein. “I grew up in Oakland, went to school in Oakland, and now I’m being treated like a complete stranger by my own government.”

Peter Spiro, a Temple University Beasley School of Law professor who specializes in constitutional and immigration law, told Al Jazeera that it is “virtually impossible” to take away an American’s citizenship. Seizing passports, he said, is one way to prevent people from traveling to the United States.

“In this case, they’re not actually seeking to formally revoke citizenship, but by taking passports away, it becomes a proxy citizenship revocation or de facto expatriation. Given that the bar to formal expatriation is so high, it’s an easier way to do it,” he said.