US Homeland Security secretary John Kelly on Wednesday unveiled enhanced security measures for foreign flights arriving in the United States in what officials said was a move to prevent an expansion of an in-cabin ban on laptops and other large electronic devices.

“Inaction is not an option,” Kelly said, saying he believed airlines will comply with the new screening. But he said the measures were not the last step to tighten security.

US officials are requiring enhanced screening of personal electronic devices, passengers and explosive detection for the roughly 2,000 commercial flights arriving daily in the United States from 280 airports in 105 countries.

The decision not to impose new restrictions on laptops is a boost to airlines, which have worried that an expansion of the ban to Europe or other locations could cause significant logistical problems and deter some travel. Airlines that failed to satisfy new security requirements could still face future in-cabin electronics restrictions, the sources said.

European and US officials told Reuters that airlines have 21 days to put in place increased explosive screening and have 120 days to comply with other security measures, including enhanced screening of airline passengers.

Reuters reported this month that the United States had suggested enhancements, including explosive trace detection screening, increased vetting of airports’ staff and additional detection dogs.

Since laptops are widely used in flight by business-class passengers – who pay double or more than the average ticket price – the airline industry had feared expanding the ban could cut into revenue.

Airlines said they would have to bear the brunt of expanded screening costs. Officials told Reuters they were concerned about adding new enhanced security measures to all of the roughly 280 airports that have direct flights to the United States rather than focus them on airports where threats are highest.

European airline groups said in a document reviewed by Reuters that if the threats were confirmed, the restrictions should be deployed to cover all EU departing flights, not just US-bound flights.

The US imposed restrictions on laptops in March on flights originating at 10 airports in eight countries, including Egypt, Saudi Arabia, Kuwait, Qatar and Turkey. They came amid fears that a concealed bomb could be installed in electronic devices taken aboard aircraft. Britain quickly followed suit with a similar set of restrictions.

None of the airlines immediately commented.

Kelly said last week that US authorities wanted to take the 10 airports off the restrictions list “by simply doing the kind of things that we’re talking about here in terms of raising aviation security.” He said the United States would boost security to a “much higher level.“

Homeland security officials plan to announce that those airports can get off the list if they meet the new security requirements.

Starting in April, Kelly repeatedly said it was “likely” the laptop ban would expand to other airports – and even said in May the government could potentially expand the ban worldwide.

One big issue facing policymakers was the potential safety implications related to past problems with laptop batteries and storing large numbers of laptops in the cargo hold.

US transportation secretary Elaine Chao said at a June Senate hearing that lithium ion batteries on airplanes can be a problem and pose a fire risk.