WASHINGTON—Intelligence showing that Daesh is developing a bomb hidden in portable electronics spurred the United States and Britain on Tuesday to bar passengers from airports in 10 Muslim-majority countries from carrying laptop computers, iPads and other devices larger than a cellphone aboard direct inbound flights, two senior U.S. counterterrorism officials said.

Two additional U.S. officials said the explosives were designed to be hidden in laptop batteries. All four spoke on condition of anonymity as they were not authorized to publicly discuss the sensitive information.

The targeting of a jetliner using explosives shows how the Islamic State, which has long worked to inspire terrorist attacks, is trying to compete with groups like Al Qaeda’s affiliate in Yemen. The affiliate has spent years inventing explosives that are difficult to detect, including trying to disguise bombs in devices like cellphones. Now, U.S. intelligence officials believe Daesh (also known as the Islamic State) has also developed explosives that can be hidden in electronic devices, one of the officials said.

Read more:U.S., U.K. ban cabin electronics in flights, but experts are asking — to what benefit?

The Trump administration maintained that the new restrictions did not signal a credible, specific threat of an imminent attack. White House spokesperson Sean Spicer declined to address the intelligence during a news briefing on Tuesday.

Republican Rep. Peter King, who sits on the House Intelligence and Homeland Security committees, said government officials called him on Saturday to alert him to the impending ban.

“It was based on intelligence reports that are fairly recent,” King said in a telephone interview. “Intelligence of something possibly planned.”

The Department of Homeland Security said the restricted items on flights to the United States included laptop computers, tablets, cameras, travel printers and games bigger than a phone. The restrictions would not apply to aircraft crews, officials said in a briefing to reporters to outline the terms of the ban.

The new policy took effect at 3 a.m. Eastern time on Tuesday, and must be followed within 96 hours by airlines flying to the United States from airports in Amman, Jordan; Cairo, Egypt; Istanbul, Turkey; Jidda and Riyadh in Saudi Arabia; Kuwait City; Casablanca, Morocco; Doha, Qatar; and Dubai and Abu Dhabi in the United Arab Emirates.

The American ban on electronics applies only to flights on foreign carriers, and not U.S.-operated airlines, which do not fly directly to the United States from the designated airports. Officials did not say how long the ban would remain in place or if other airports would be added.

In all, an estimated 50 flights each day into the U.S. would be affected. One of the world’s busiest airports, in Abu Dhabi, already requires American-bound passengers to undergo strict screening by U.S. customs officials before boarding flights. Abu Dhabi is one of 15 airports in the world to employ the Homeland Security preclearance techniques.

Several hours after the U.S. action, the British government announced its own ban on electronic devices on flights.

The British ban affects domestic and foreign airlines, including British Airways, the country’s largest. Foreign airlines affected by the order include Turkish Airlines, EgyptAir and Royal Jordanian, among others, and it affects direct flights to the United Kingdom from Turkey, Lebanon, Jordan, Egypt, Tunisia and Saudi Arabia.

In all, airports in 10 countries are affected by the new restrictions.

A British official said the U.K. ban resulted from the combination of an evolving threat picture and a proliferation of electronic devices that airline passengers carry on board.

Examples of attacks by extremist groups against transportation hubs over the past two years include the October 2015 bombing of an airliner in Egypt, the attempted airliner downing in Somalia last year and armed attacks against airports in Brussels and Istanbul in 2016.

The new bans on electronic devices have prompted a round of protests from passengers who now face the prospect of flying long hours without the use of laptops or tablets.

Banu Akdenizli, an associate professor of communication at Northwestern University’s campus in Doha, complained that the ban would affect her ability to work during a long flight to Greensboro, N.C., for a conference in April.

“This is a 20-hour flight,” she said. “I think as an academic or any business traveller, the function of a work flight is to be able to work on it, especially if you’re going to a conference.”

Osama Sharshar, a prominent Egyptian lawmaker and journalist who frequently travels to the U.S., was critical of the changes and suggested President Donald Trump issued the order simply to “please the right-wing extremists in America.”

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“It will terribly affect me as a journalist, a lawmaker and a regular Egyptian,” he said. “I work on planes all the time. And the flight to the States is very long.”

The Homeland Security Department’s new ban appeared to take officials from some of the affected countries by surprise.

Ahmet Arslan, Turkey’s transport, maritime and communication minister, said the ban would be harmful to the United States’ airline industry — and to Turkey’s.

“Our problem is not how the practice would take place,” Arslan said. “The issue is, it can decrease the comfort of the passengers and reduce the numbers of passengers. We are emphasizing that this is not in the benefit of passengers, and we think that they should step back from this or ease it.”

Counterterrorism experts seemed equally divided over the need for the device ban.

Michael Chertoff, the former Homeland Security secretary, said the new policy made sense given the threats to aircraft from explosive devices and concerns about screening at the targeted airports.

“The challenge is to balance security without making it impossible to fly,” Chertoff said.

But Erroll Southers, director of the Homegrown Violent Extremism Studies Program at the University of Southern California, said the new guidance would do little to enhance security.

“This does little to minimize the threat of a remote-controlled IED,” he said, referring to improvised explosive devices hidden in checked baggage.

U.S. intelligence officials did not cite threats against domestic airports, but one said the Transportation Security Administration has been on heightened alert at several airports. It was not clear if that alert was related to the new restrictions on electronic devices.

The restrictions follow other recent changes the TSA has made in aviation security. Two weeks ago, the agency adopted enhanced pat-down searches for passengers at U.S. airports, a response to what it said were weaknesses in airport screening measures. Under the new rules, passengers will no longer be allowed to choose what type of searches they undergo in security lines.

The agency said the measures, which will be more invasive than current procedures, were needed to improve the ability of screeners to detect explosives or other banned items. In a series of 70 undercover tests of airport security screening procedures, conducted in 2015 by the Homeland Security inspector general’s office, auditors were able to get fake weapons and explosives past security screeners 95 per cent of the time, according to the still-classified report.

The enhanced pat-down searches will be used on passengers who refuse to go through the full-body screening machine. Passengers who trigger alarms while going through screening will also undergo the enhanced searches. TSA officers can also randomly choose passengers for the more invasive pat-downs.