On Thursday, a Wall Street Journal (WSJ) reporter claimed that the Department of Homeland Security demanded access to her mobile phones when she was crossing the border at the Los Angeles airport.

The case highlights the powers that border agents purport to have, and how vulnerable sensitive information can be when taken through airports in particular.

“I wanted to share a troubling experience I had with the Department of Homeland Security (DHS), in the hopes it may help you protect your private information,” Maria Abi-Habib, a WSJ journalist focused on ISIS and Al Qaeda wrote in a post on Facebook. (Abi-Habib confirmed to Motherboard that the Facebook account was hers, but declined to comment further.)

Abi-Habib says she had arrived in town for a wedding, when an immigration officer approached her, and took her aside from the main queue. This by itself was not unusual, Abi-Habib writes: because of her job, she has reportedly been put on a list that allows her to bypass the usual questioning someone with her travel profile may encounter.

But things changed quickly, and Abi-Habib was escorted to another part of the airport.

“Another customs agent joined her at that point and they grilled me for an hour—asking me about the years I lived in the US, when I moved to Beirut and why, who lives at my in-laws’ house in LA and numbers for the groom and bride whose wedding I was attending. I answered jovially, because I’ve had enough high-level security experiences to know that being annoyed or hostile will work against you,” she writes.

The first DHS agent then asked Abi-Habib for her two cell phones, in order “to collect information,” Abi-Habib reports the officer as saying.

“And that is where I drew the line,” Abi-Habib writes. “I told her I had First Amendment rights as a journalist she couldn’t violate and I was protected under. I explained I had to protect my government and military sources—over the last month, I have broken two stories that deeply irked the US government, in addition to other stories before I went on maternity leave, including one in Kabul that sparked a Congressional investigation into US military corruption, all stories leaked by American officials speaking to me in confidence.”

The agent passed over a document, which Abi-Habib later photographed and posted to Facebook, purportedly showing that the agent has the right to seize those devices. Abi-Habib instead said that the border agents would need to contact WSJ’s lawyers. After some back and forth, the agent went to see her supervisor, and eventually said Abi-Habib is free to go.

Abi-Habib said she reported the incident to a WSJ lawyer, encryption expert and the outlet’s in-house security. From those conversations, Abi-Habib says, “My rights as a journalist or US citizen do not apply at the border, as explained above, since legislation was quietly passed in 2013 giving DHS very broad powers (I researched this since the incident). This legislation also circumvents the Fourth Amendment that protects Americans’ privacy and prevents searches and seizures without a proper warrant.”

Back in 2013, WIRED reported on those changes, writing “The Department of Homeland Security’s civil rights watchdog has concluded that travelers along the nation’s borders may have their electronics seized and the contents of those devices examined for any reason whatsoever—all in the name of national security.”

Abi-Habib continues, “Why I was eventually spared, we do not know and we are writing a letter contesting DHS’ treatment of me. I assume they avoided seizing my phones forcefully because they knew we would make a stink about it and have a big name behind us.”

Abi-Habib closes with a series of security tips for those with sensitive information crossing the border, such as encrypting devices, but bearing in mind that information can be demanded from you.

“Travel ‘naked’ as one encryption expert told me. If any government wants your information, they will get it no matter what,” she adds.

The DHS did not immediately respond to a request for comment. The Wall Street Journal sent a statement from Editor in Chief Gerard Baker:

“We are disturbed by the serious incident involving WSJ reporter Maria Abi-Habib, a citizen of the United States and Lebanon.”

“We have been working to learn more about these events, but the notion that Customs and Border Protection agents would stop and question one of our journalists in connection with her reporting and seek to search her cell phones is unacceptable.”

The document scanned by Abi-Habib: