Senior U.S. homeland security officials briefed ­European officials Wednesday about an “evolving aviation security threat” that may prompt an expansion of a ban on carry-on laptops and electronic devices on U.S.-bound flights, after President Trump disclosed highly classified intelligence to Russia about a ­laptop-related terrorism plot.

The meeting in Brussels — a portion of which occurred in a classified setting — came after European officials were surprised last week by media reports of a potentially expanded ban. Europeans were worried that it would possibly disrupt travel with little security payoff. The Department of Homeland Security has said it has not yet made a decision.

The classified briefing underlined the awkward situation U.S. allies have been put in by Trump’s decision last week to share sensitive information during an Oval Office visit by Russian Foreign Minister Sergei Lavrov. That put Russia — a U.S. adversary — in the position of knowing more about sensitive security intelligence than Washington’s closest counterterrorism partners.

Deputy Homeland Security Secretary Elaine Duke conferred Wednesday with Dimitris Avramopoulos and Violeta Bulc, the top E.U. officials in charge of migration and transportation. “At the meeting, both sides exchanged information on the serious evolving threats to aviation security and approaches to confronting such threats,” the European Commission and the Department of Homeland Security said in a joint statement after the meeting.

European officials have complained about being in the dark.

[Travel groups, airlines brace for possible expansion of laptop ban to all flights from Europe]

“Any threats that affect the U.S. are the same for Europe. So information should be shared. We explained that. And our response should be one in common,” European Commission spokesman Enrico Brivio said before the meeting, voicing European concerns that the United States was about to take unilateral action without explaining the threat to its partners.

The U.S. delegation appears to have started those explanations Wednesday — a week after Trump shared related information with the Kremlin. Another meeting will be held in Washington next week.

“We did provide certain European partners specific insight into the specific and current and I would say evolving aviation security threat around the electronic restrictions,” a senior U.S. official said, briefing reporters after the meeting on the condition of anonymity.

The ban took on new political overtones this week after The Washington Post reported that Trump disclosed classified information to Russia’s top diplomat about a plot to sneak bombs onto planes in laptop computers. The intelligence came from a U.S. partner and was considered so sensitive that it was distributed among only a small circle within the U.S. government and was withheld from broader sharing among ­English-speaking allies that U.S. intelligence agencies do as a matter of course.

[Putin offers to provide Congress with details of Trump disclosures to Russian envoys]

The broad topic of a bomb threat was less sensitive than the specific intelligence, which contained information that from its context could jeopardize the ­intelligence-gathering abilities of the U.S. ally. Administration officials have insisted that Trump did nothing wrong in the disclosure.

A laptop ban has drawn skepticism from transportation and security groups in Europe. The U.S. ban currently covers flights from 10 airports in eight Muslim-majority countries. Media reports have indicated that it might be extended to European flights.

The European Aviation Safety Agency, the E.U. counterpart to the Federal Aviation Administration, counseled in April the exact opposite of the U.S. proposal, telling airlines that personal electronic devices “should preferably be carried in the passenger cabin” so that flight attendants could more easily address fires if ­lithium-ion batteries combust. The agency declined to comment Wednesday but said that last month’s guidance was still valid.

Industry groups worry about the economic consequences of expanding the ban to more flights. The head of the International Air Transport Association (IATA) expressed serious concerns Tuesday about the ban and urged leaders to consider other enhanced screening methods as an alternative.

Expanding the ban could cost $1.1 billion a year in lost productivity, travel time and “passenger well-being,” Alexandre de Juniac, director general and chief executive of the group, which represents 265 airlines, wrote in a letter to Bulc and Homeland Security Secretary John F. Kelly.

Although the current ban affects travelers on about 350 flights a week, an expansion could affect 390 flights a day, de Juniac wrote.

“IATA fully acknowledges that security remains the primary responsibility of States, and we understand that the US, the UK and other States have compelling reasons to mandate the implementation of counter-measures in response to credible threat intelligence,” he wrote.

De Juniac suggested expanding random explosives screenings at airports, which he said would improve security but would be less disruptive. Other possibilities include deploying more specially trained security officers and ­explosives-detecting dogs.

Aratani reported from Washington. Annabell Van den Berghe in Brussels contributed to this report.

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