By Jay Croft CNN

(CNN) -- A US citizen and NASA engineer returning from a trip abroad says he was held at the border by US Customs officers who demanded that he unlock his phone.

Sidd Bikkannavar said in a post on social media that US Customs and Border Protection officers wanted his cell phone -- and password -- before they would let him through at Houston's George Bush Intercontinental Airport.

"On my way home to the US last weekend, I was detained by Homeland Security and held with others who were stranded under the Muslim ban," Bikkannavar wrote in a Facebook post shared by a friend on Twitter. "I initially refused, since it's a (NASA)-issued phone and I must protect access," Bikkannavar wrote.

"Just to be clear -- I'm a US-born citizen and NASA engineer, traveling with a valid US passport. Once they took both my phone and the access PIN, they returned me to the holding area with cots and other sleeping detainees until they finished copying my data."

'There's no magic formula'

Bikkannavar said he was returning to the United States shortly after President Donald Trump issued an executive order blocking immigrants from seven Muslim-majority nations and all refugees.

Since the order, a Muslim civil rights organization says it has filed 10 complaints with CBP, the Department of Homeland Security and the Department of Justice alleging systematic targeting of American-Muslim citizens for enhanced screening by CBP.

The Council on American Islamic Relations reports increased scrutiny of American-Muslims' social media accounts and contents of their mobile phones since Trump's ban, which has since been blocked in court.

CAIR-Florida spokseman Wilfredo A. Ruiz says citizens must surrender laptops and phones if a border agent asks for them, but not the passwords or social media information. Border agents might give the device back and let the person go. Or they might hold onto it and seek a warrant to break it open. Or a wide range of responses in between.

"Sometimes they play hardball and delay you, maybe cause you to miss your flight or get home hours later," he said. "There's no magic formula."

CNN has attempted to contact Bikkannavar, CBP and the Jet Propulsion Laboratory where Bikkannavar works for comment. This story will be updated as more information becomes available.

Ruiz, a convert to Islam, said he doesn't know if Bikkannavar is a Muslim, and that it doesn't matter. "This widens the scope of those being targeted to those who are not perceived as being the traditional, white American," Ruiz said. "It is not a Muslim issue."

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