The US has announced a ban on large electronic devices from cabin baggage on passenger flights from eight Muslim majority countries.
The Department of Homeland Security (DHS) said extremists were seeking "innovative methods" to bring down jets.
Bombs could be hidden in laptops, tablets, cameras, DVD players and electronic games, it said.
The measure will affect nine airlines operating out of 10 airports. Large electronic devices will only be allowed on board in checked baggage. Phones are exempt from the new rules.US officials said the airlines had been given 96 hours, beginning at 07:00 GMT on Tuesday, to ban devices bigger than a mobile phone or smartphone from cabins. They said the ban had no end date.