The Trump administration may expand a current laptop ban to cover all international flights to and from the US, the head of homeland security said this week. In an interview with “Fox News Sunday”, Homeland Security Secretary John Kelly said airlines face a “sophisticated threat” from terrorists seeking to bring down US-bound flights, though he noted that a final decision on expanding the ban has not been made.

“That’s really the thing that they’re obsessed with, the terrorists: the idea of knocking down an airplane in flight, particularly if it’s a US carrier, particularly if it’s full of mostly US folks,” Kelly said Sunday.

The current electronics ban, implemented in March, applies to US-bound flights from eight majority-Muslim countries. The measure prohibits passengers from bringing any devices that are “larger than a smartphone” as carry-on items, and was implemented, US officials say, to thwart terrorist plots to bring down planes with smaller bombs. The UK has issued a similar ban covering flights from six countries.

American officials recently met with European leaders to discuss expanding the travel restriction to flights between the US and EU. The proposed expansion was reportedly shelved following talks in Brussels, though officials said “other measures” were still on the table. Last week, Politico reported that US airlines are still preparing for an “imminent” expansion of the ban to Europe and possibly other regions.

The proposed expansion to Europe has drawn criticism from the International Air Transport Association (IATA), which said last week that the measure would cost travelers an additional $1.1 billion per year. IATA Director General Alexandre de Juniac recently called on officials to consider “alternative measures,” including better bomb detection devices.

In his interview with “Fox News Sunday,” Kelly acknowledged that the US will rely on “new technologies down the road” to improve the screening of electronics. As Bloomberg reported last week, at least four companies that produce screening machines are working on more advanced scanners to detect explosives. If the scanners are put into use, the companies say, passengers would be able to leave electronics and liquids in their bags during the screening process.