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U.S. Customs and Border Protection officers searched the cell phones of nearly 25,000 travelers entering or leaving the U.S. in 2016, including phones belonging to naturalized citizens and people born and raised in America. "[The travelers] traveled by plane and by car at different times through different states," NBC News writes. "Businessmen, couples, senior citizens, and families with young kids, questioned, searched, and detained for hours when they tried to enter or leave the U.S. None were on terror watchlists. One had a speeding ticket. Some were asked about their religion and their ethnic origins, and had the validity of their U.S. citizenship questioned."

In February 2017 alone, agents searched 5,000 phones; CBP agents searched fewer than 5,000 phones in all of 2015. "That [increase] was clearly a conscious strategy, that's not happenstance," said Mary Ellen Callahan, the former chief privacy officer of the Department of Homeland Security, calling the skyrocketing searches "shocking."

NBC's investigation found that most of the people being stopped were Muslim. Senior intelligence officials revealed that the uptick of searches follows domestic events in 2015 and 2016, when American citizens conducted attacks on U.S. soil, but others say that talk of Muslim registries and bans has loosened the reins on federal agents to act more aggressively.

"This really puts at risk both the security and liberty of the American people," said Sen. Ron Wyden (D-Ore.). "Law-abiding Americans are being caught up in this digital dragnet."