Heightening the concern is US intelligence suggesting that terrorists have obtained sophisticated airport security equipment to test how to effectively conceal explosives in laptops and other electronic devices.

The intelligence, gathered in the last several months, played a significant role in the Trump administration’s decision to prohibit travelers flying out of 10 airports in eight countries in the Middle East and Africa from carrying laptops and other large electronic devices aboard planes.

The findings may raise questions about whether the ban is broad enough. CNN has learned that, through a series of tests conducted late last year, the FBI determined the laptop bombs would be far more difficult for airport screeners to detect than previous versions terrorist groups have produced. The FBI testing focused on specific models of screening machines that are approved by the Transportation Security Administration and are used in the US and around the world.