US-bound travelers face heightened screening amid 'web of threats to commercial aviation' Short, verbal interviews will occur at the gate or check-in, sources say.

 -- Beginning today, passengers booked on U.S.-bound international flights with at least four different airlines will be required to complete a short, verbal security interview before they board, sources told ABC News.

Air France, Lufthansa, Emirates and Cathay Pacific confirmed that they will begin interviewing passengers on select flights today, with additional routes and other carriers expected to follow suit shortly.

The interviews will be conducted during document check, check-in or at the gate, the airlines told ABC.

The new procedures come as part of an initiative announced in June by then–Homeland Security Secretary John Kelly to "raise the global baseline of aviation security."

Rather than specifically mandating passenger interviews, the Department of Homeland Security and Transportation Security Administration instructed airlines to submit plans that would meet the enhanced passenger screening requirements initiated by Kelly.

Like the electronics screening requirement, the enhanced passenger screening requirements affect 280 airports in 105 countries running about 2,000 flights, with about 325,000 passengers per day.

Though many airlines opted to do interviews, some may meet the requirements in other ways.

The Kelly initiative came amid a "web of threats to commercial aviation" as terrorists try to smuggle explosives onto jets inside laptops or other electronics, according to the DHS.

"We cannot play international whack-a-mole with each new threat," Kelly said told reporters in June. "Instead, we must put in place new measures across the board to keep the traveling public safe and make it harder for terrorists to succeed."

"Security adjustments rooted in legitimate concerns are a fact of life for travelers," U.S. Travel Association Executive Vice President Jonathan Grella said in a statement today, adding that all changes in security posture should be "clearly communicated," "continually reassessed" and "tailored to specific vulnerabilities."

"Legitimate business and leisure travelers are as welcome as ever in the United States," he said.

ABC News' Jeffrey Cook contributed to this report