Arnd Wiegmann / Reuters

Updated at 8:45 a.m.

The Department of Homeland Security will no longer allow passengers to carry electronics onto flights to the U.S. from 10 major airports in the Middle East and North Africa. Devices larger than a mobile phone—including laptops, tablets, and cameras—will need to be placed in checked baggage.

The airports are located in eight countries: Egypt, Jordan, Kuwait, Morocco, Qatar, Saudi Arabia, Turkey, and the United Arab Emirates. (Two airports were designated in Saudi Arabia and in the UAE.) Nine airlines—none of them American or European—will be responsible for enforcing the rules. The Department of Homeland Security said about 50 flights a day will be affected by the rules.

The ban was communicated to the relevant airlines and airports at 3 a.m. Eastern on Tuesday, in the form of an emergency amendment to a security directive. From that point, the airlines and airports will have 96 hours to comply. If they fail to, a senior administration official told reporters, “we will work with the Federal Aviation Administration to pull their certificate, and they will not be allowed to fly to the United States.”

The ban on larger electronics was developed in response to a “continuing threat to civil aviation,” according to another official, who would not say whether the threat had developed recently, or when the ban might be lifted. DHS is concerned about a trend of bombs being disguised as consumer items, like shoes, a printer, and even a laptop. The official said the data on checked electronics would not be searched.

Items in checked baggage are generally subjected to intense screening, and security officers sometimes open bags to look through them by hand. Requiring electronics to be checked could allow the Transportation Security Administration to scan them more closely than they would otherwise. In 2014, TSA officers began asking passengers to power on their devices to prove that they’re real—and not just a clever disguise for an explosive.

But relegating most electronics to a plane’s cargo hold comes with potential dangers. In the past, the Federal Aviation Administration has expressed concerns about checking too many lithium-ion batteries—the sort that power laptops—because they can catch fire. A senior administration official said the FAA is sharing information about “best practices” for transporting electronics with the affected airlines.

It will be up to airlines to differentiate between smartphones, which will be allowed in airplane cabins, and tablets, which will need to be checked. Some large smartphones, often called “phablets,” blur this boundary.

Royal Jordanian, the state airline of Jordan, was the first to notify its passengers of the new rules on Monday afternoon. The carrier, which operates flights to New York City, Detroit, and Chicago multiple times a week, announced the change in a tweet—which it went on to delete several hours later.

The tweet sparked hours of confusion, during which U.S. officials were tight-lipped. The Jordanian airline’s statement said only that the new policy “follow[ed] instructions from the concerned U.S. departments.”

A spokesperson for the Jordanian Embassy in Washington, D.C. said the airline’s policy was requested by the State Department. A senior administration official told reporters that the State Department had begun notifying governments of the upcoming ban on Sunday.

Edward Hasbrouck, a travel expert and consultant to The Identity Project, said government has a history of announcing big policy changes with little notice. “This reminds me of the chaos when the DHS started restricting liquids, which occurred with no warning and people found out only at the airport,” he said.

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