Journalists covering the arrival of caravans of migrants from Central America along the U.S. southern border have faced harassment, additional screenings, and targeting by both U.S. and Mexican authorities.

The U.S. Press Freedom Tracker has documented at least five journalists who have been stopped on the U.S. side of the border since December 2018 in the course of doing their jobs covering the migrant caravan. Some have been stopped numerous times, where they are put in situations that could threaten their privacy, reporting processes, and confidential sources.

In addition, Mexican authorities denied entry to at least two journalists — along with two immigration attorneys — who were attempting to travel to the country last month, making headlines and sparking concerns about public access and press freedom issues along the border.

The journalists’ — Kitra Cahana and Daniel Ochoa — and the attorneys’ accounts of what happened were nearly identical. Mexican authorities detained them when they attempted to enter, informed them that their passports were “flagged,” and then turned them away.

“I’m in limbo,” Cahana told the Los Angeles Times. “What kind of list am I on? Who put me on this list? And how many journalists is this affecting?”

It’s unclear whether it was the Mexican or United States government that placed an alert on their travel documents, but both journalists reported that their passports had previously been photographed by both U.S. and Mexican authorities.

These passport alerts have not only impacted journalists trying to enter Mexico, but also those attempting to enter the United States. While entering the country via San Diego at the end of last year, freelance journalist Ariana Drehsler was told by border authorities that her passport had been flagged, but that they did not know why.

Customs and Border Protection did not provide details on what these “flags” on passports like Drehsler’s might be or why they may have been placed. But since then, she has been subjected to secondary screenings — including questionings that made her feel like “an informant,” and searches — every time she has entered the United States. She isn’t the only one.

Manuel Rapalo, a journalist who freelances for Al Jazeera, said he has been stopped at least three times at the U.S.-Mexico border in 2019. (Read details about each border stop on the US Press Freedom Tracker.)

Out of concern about the frequency of equipment searches during these stops, he said he has changed his behavior to ensure his sources and reporting materials are protected. He brings new memory cards with him on each reporting trip to minimize what material could end up in border officials’ hands.

The numerous journalists stopped at the border and questioned about their work while covering the arrival of Central American immigrants to Mexico aren’t the only ones that have been targeted by CBP recently. In January, a filmmaker had his device taken by order officials, who demanded he unlock his phone and then took it into a different room. And when an Al-Jazeera anchor had his device seized at the border, CBP agents asked him about his social media accounts.

A recent report by the Committee to Protect Journalists found that between 2006 and June 2018, the 37 journalists surveyed for the report were collectively stopped for screenings more than 110 times. In many cases, journalists were asked to unlock their electronic devices, answer invasive questions about their reporting, and had their personal belongings searched. In a particularly egregious case in 2016, well-known photojournalist and Canadian citizen Ed Ou was even denied entry into the United States.

CPJ found that CBP’s broad and relatively unchecked powers pose a significant press freedom threat — particular since the agency can share the information it gains for journalists’ devices with other federal agencies, including sources and sensitive documents.

“With a more aggressive administration openly hostile to the press and leaks, CBP should implement tighter guidelines to protect the First Amendment rights of all individuals crossing the border,” CPJ concluded.

“Press freedom rights should not cease at the border,” said Freedom of the Press Executive Director Trevor Timm. “These egregious and invasive border stops are a threat to both journalists and their sources, and they give authoritarian countries every excuse to use similar tactics on their borders as well. CBP and the Trump administration need to publicly account for these disturbing events.”