Border police customarily should receive domestic and international travelers with a "welcome home" note, but that was not the case for Abdirahman Aden Kariye. Kariye, a Muslim American Imam in Bloomington, Minnesota, says he has received no such greetings.

Kariye, the son of Somali immigrants who immigrated to the United States, told ABC News that his airport experiences are characterized by a tremendous sense of worry. He says he is frequently "singled out" and taken into secret rooms by US border officers for hours-long interrogations.

“I've been stopped many times, almost 90% of the time,” Kariye said, recounting his experience traveling domestically and internationally.

He says that in recent years, these additional inspections upon his return from abroad visits have been accompanied by a barrage of questioning probing his religious views and practices.

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“Those experiences made me feel that I had to make myself less visible as a Muslim,” Kariye said, confirming that the questioning brought on so much anxiety that while traveling, he stopped praying at the airport, stopped carrying religious texts written in Arabic, and even stopped wearing his kufi, a brimless cap that some Muslim men wear around the world.

“I feel like I don't have the freedom to be a Muslim in America,” he added.

According to Kariye, some of the questions asked by US border officers included what type of Muslim he is, whether he is Sunni or Shia, how many times a day he prays, what mosque he attends, his views on a particular Muslim scholar, whether he listens to music, whether he studies Islam, and where he studies Islam.

“When you ask these types of questions about my personal beliefs … you're telling me that you have a suspicion about Muslims, that they are, you know, inherently a threat to national security,” Kariye said.

Complaint filed 

On Thursday, the American Civil Liberties Union filed a federal complaint on behalf of Kariye and two other Muslim Americans who were reportedly subjected to similar religious interrogation at the border.

The lawsuit was filed against the Department of Homeland Security and US border officials in the United States District Court for the Central District of California on behalf of Kariye, Mohamad Mouslli, and Hameem Shah, who say that border officers repeatedly asked them detailed questions about their religion.

According to the lawsuit, Shah is a US citizen who lives in Plano, Texas, and works in financial services, whereas Mouslli works in commercial real estate and lives in Gilbert, Arizona, with his wife and three children.

The lawsuit claims that the questions violated the plaintiffs' constitutional rights by infringing on their First Amendment right to religious freedom, as well as the Religious Freedom Restoration Act (RFRA), a 1993 law passed by Congress.

“Because this questioning imposes substantial pressure on the plaintiffs to hide their religious expression when they're traveling – to alter it at the airport, and because it serves no legitimate law enforcement purpose, it violates the [RFRA], and it also violates the Constitution,” Ashley Gorski, a senior staff attorney with the ACLU’s National Security Project, told ABC News.

ABC News reached out to DHS and CBP but requests for comment were not returned.