One day after the Trump administration imposed restriction on carry-on electronic devices on planes coming to the United States from 10 airports in Muslim-majority countries in the Middle East and North Africa in response to unspecified terrorism threats, moments ago the UK issued a similar ban, restricting the use of carry on laptops and tablets for inbound flights for flights originating in the following middle-eastern nations: Turkey, Lebanon, Jordan, Egypt, Tunisia, and surprisingly, Saudi Arabia.

And so what last night appeared to some to be a capricious decision by the Trump administration, may have been prompted by some actionable intel since the UK has joined the action.

According to Downing Street, no phones, tablets, or laptops bigger than 16cm length, 9.3cm wide and 1.5cm deep would be allowed in the main cabin of the plane. The devices will need to be placed into hold luggage and checked-in instead.

“The safety and security of the travelling public is our highest priority,” said a government spokesperson. “In the last few weeks we have had a number of meetings on aviation security. This morning at a meeting we agreed that these new measures were required.”

According to the FT, the spokesperson declined to explain how the decision was made, saying, “we would not get into the information on which this decision was taken but we think these steps are necessary and proportionate. We have spoken closely with the US [about which countries they have included] but we have each taken our own decisions on this.”

UK carriers affected by the ban are: British Airways, EasyJet, Jet2.com, Monarch, Thomas Cook and Thomson.

While we await more detais, a reminder that on Monday afternoon, the DHS said passengers traveling from a selection of airports could not bring devices larger than a cellphone, such as tablets, portable DVD players, laptops and cameras, into the main cabin. Instead, they must be in checked baggage. The new restrictions were prompted by reports that militant groups want to smuggle explosive devices in electronic gadgets, officials told reporters on a conference call on Monday. They did not provide further details on the threat.

The airports 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.

Officials said the decision had nothing to do with President Donald Trump's efforts to impose a travel ban on six majority-Muslim nations. DHS spokeswoman Gillian Christensen said the government "did not target specific nations. We relied upon evaluated intelligence to determine which airports were affected."

The airports affected by the electronics rules are served by nine airlines that fly directly from those cities to the United States about 50 flights a day, senior government officials said.

The carriers - Royal Jordanian Airlines, Egypt Air, Turkish Airlines, Saudi Arabian Airlines, Kuwait Airways [KA.UL], Royal Air Maroc, Qatar Airways, Emirates and Etihad Airways - have until Friday to comply with the new policy, which took effect early on Tuesday and will be in place indefinitely.

Several of the carriers, including Turkish Airlines, Etihad and Qatar, said early on Tuesday that they were quickly moving to comply. Royal Jordanian and Saudi Airlines said on Monday that they were immediately putting the directive into place.

An Emirates spokeswoman said the new security directive would last until Oct. 14. However, Christensen termed that date "a placeholder for review" of the rule.

The policy does not affect any American carriers because none fly directly to the United States from the airports, officials said. Officials did not explain why the restrictions only apply to travelers arriving in the United States and not for those same flights when they leave from there. The rules do apply to U.S. citizens traveling on those flights, but not to crew members on those foreign carriers. Homeland Security will allow passengers to use larger approved medical devices.

Angela Gittens, director general of airport association ACI World, likened the move to years-long restrictions of liquids on planes, which she said also came suddenly, in response to a perceived threat, and caused some disruption. Airlines will adjust to the electronics policy, she said. "The first few days of something like this are quite problematic, but just as with the liquids ban, it will start to sort itself out."

DHS said the procedures would "remain in place until the threat changes" and did not rule out expanding them to other airports.