"This clarifying update will strengthen global aviation security and is a testament to our shared commitment to raising the baseline," said James Gregory, a spokesman for the U.S. Transportation Security Administration, which is part of the DHS.
An airline official briefed on the matter said the directive gives airlines more flexibility and additional time to obtain explosive trace detection equipment. The official was not authorized to discuss sensitive security issues with the media and requested anonymity.
The directive includes technical adjustments, agency officials said, declining to release the text. European airlines have been pushing for changes to meet the new requirements, which begin taking effect on July 19.
The new requirements include enhanced passenger screening at foreign airports, increased security protocols around aircraft and in passenger areas and expanded canine screening. They affect 325,000 airline passengers on about 2,000 commercial flights arriving daily in the United States, on 180 airlines from 280 airports in 105 countries.
On June 28, U.S. Homeland Security Secretary John Kelly unveiled enhanced security measures for all foreign flights arriving in the United States, which officials said were designed to end a limited in-cabin ban on laptops and prevent the ban's expansion to additional airports.
In March, DHS imposed restrictions on passengers carrying large electronics like laptops in cabins on nine airlines, most of which were Middle Eastern carriers, to address the potential threat of hidden explosives.
European and U.S. officials told Reuters that airlines had 21 days from June 28, or until July 19, to put in place increased explosive trace detection screening and 120 days to comply with other security measures, including enhanced screening of airline passengers.
One issue, European airline officials said, was whether some explosive screening could be done at a central point, rather than at gates.
DHS spokesman David Lapan said this week that U.S. officials are working with airlines. "Some airports, airlines will be able to get there more quickly," Lapan said.
Gregory separately denied a report that the new measures could require in-person check in for U.S. flights. "None of the measures impact the ability of an airline to offer kiosk or on-line check in," he said.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)