Britain has followed the United States to introduce restrictions on carry-on electronic goods on direct inbound flights from Turkey, Lebanon, Jordan, Egypt, Tunisia and Saudi Arabia.
Yesterday it was revealed the United States would impose similar restrictions on planes coming from 10 airports in Muslim-majority countries in the Middle East and North Africa in response to unspecified security threats.
"Direct flights to the UK from these destinations continue to operate to the UK subject to these new measures being in place," a spokesperson for UK Prime Minister Theresa May said today.
"We think these steps are necessary and proportionate to allow passengers to travel safely."
Passengers will not be allowed to bring phones, laptops, or tablets over 16 cm in length, 9.3 cm in width and with a depth of over 1.5 cm into the cabin.
These items will have to be in checked-in hold luggage. The foreign office said the measures would be implemented by March 25.
The move has come despite concerns by civil liberties groups that US President Donald Trump was seeking another limit on movement after a travel ban from Muslim-majority countries was challenged in the courts.
The US government said the decision was prompted by reports that militant groups want to smuggle explosive devices inside electronic gadgets.
The ban would be in place for the "foreseeable future," a US government official said, adding that it was possible it could be extended to other airports and other countries.
White House spokesman Sean Spicer declined to talk about the intelligence that prompted the new steps or explain why some countries were left off the list.
Senator Bill Nelson, a Florida Democrat, sclaimed he "spoke to the intelligence community over the weekend, and this is a real threat."
US officials say militant groups are known for innovative bomb designs, including embedding them inside computers. Yemen-based Al Qaeda in the Arabian Peninsula (AQAP) also has boasted of one of the world's most feared bomb makers, Ibrahim Hassan al-Asiri.
French and Canadian officials said they were examining their arrangements but neither government was taking additional security measures at this stage.
The Australian government has said it will not implement a similar ban.
The airports covered by the US restrictions are in Cairo; Istanbul; Kuwait City; Doha, Qatar; Casablanca, Morocco; Amman, Jordan; Riyadh and Jeddah, Saudi Arabia; and Dubai and Abu Dhabi in United Arab Emirates.
The affected airports are served by nine airlines that fly directly from those cities to the United States about 50 times a day, senior government officials said.
The carriers - Royal Jordanian Airlines, Egypt Air, Turkish Airlines, Saudi Arabian Airlines, Kuwait Airways, Royal Air Maroc, Qatar Airways, Emirates and Etihad Airways - have until Friday to adopt the new policy, which took effect yesterday.
No US airlines are on the list because there are no direct flights on them between the United States and the cited airports, officials said.
Britain said its restrictions would apply to direct flights from Turkey, Lebanon, Jordan, Egypt, Tunisia and Saudi Arabia.
The British regulations affect British Airways, easyJet, Jet2, Monarch, Thomas Cook, Thomson, Atlas-Global, Pegasus, EgyptAir, Royal Jordanian, Middle East Airlines, Saudia, Turkish Airlines and Tunisair.
A US government source said that while the restrictions arose from multiple reports of security threats, some recent intelligence had arrived that prompted the current alert.
US authorities believe there is a threat from plots similar to an incident last year in Somalia, where a bomb hidden in a laptop blew a hole in the side of a plane but failed to down it, another source said.
However, some experts questioned whether the limited ban could improve security and said it is complicated by aviation safety concerns about lithium-powered batteries used in many electronic items catching fire in the hold.
US officials said the decision had nothing to do with Trump's efforts to impose a travel ban on citizens of six majority-Muslim nations.
On March 6, Trump signed a revised executive order barring citizens from Iran, Libya, Syria, Somalia, Sudan and Yemen from traveling to the United States for 90 days. Two federal judges have halted parts of the ban although Trump has vowed to appeal.