The Trump Administration on Monday barred passengers on 13 airlines flying from the Middle East and Africa from bringing laptops, iPads, cameras and other electronic devices in carry-on luggage on some US-bound flights starting Tuesday.

Royal Jordanian Airlines said in a tweet that cellphones and medical devices are excluded from the ban, but other electronic items would have to be sent in checked luggage.

Saudi Arabia’s Saudia Airlines was also affected.

It was unclear what other countries and airlines are affected, how long the ban will be in place or what prompted it.

Homeland Security Secretary John Kelly phoned lawmakers over the weekend to brief them on aviation security issues that have prompted the impending electronics ban, according to a congressional aide briefed on the discussion.

A government source told AP that such a ban had been considered for several weeks.

David Lapan, a spokesman for Homeland Security, declined comment.

Royal Jordanian said the electronics ban affects its flights to New York, Chicago, Detroit and Montreal.

An aviation security expert said the policy would raise other safety issues.

“There would be a huge disadvantage to having everyone put their electronics in checked baggage,” said Jeffrey Price, a professor at Metropolitan State University of Denver.

He said thefts from baggage would skyrocket, just as when England tried a similar policy in 2006.

“Some laptops have batteries that can catch fire and it’s easier to detect it when it’s in the cabin rather than burning in the hold,” he said.

However, there are also advantages to screening items in checked baggage instead of as carry-on luggage.

Most major airports in the US have a computer tomography or CT scanner for checked baggage, which creates a detailed picture of a bag’s contents.

They can warn an operator of potentially dangerous material, and may provide better security than the X-ray machines used to screen passengers and their carry-on bags.

Jordan is a long-standing ally of the US.