WASHINGTON — Despite the discovery of a sophisticated new al-Qaida airline bomb plot, congressional and security officials today suggested no immediate need to change to airport security procedures, which already subject shoeless passengers to pat-downs and body scans.

The CIA, with help from an informant and foreign intelligence services, conducted a covert operation in Yemen in recent weeks that disrupted a nascent suicide plot and recovered a new bomb, U.S. officials said.

Officials said the bomb represents an upgrade over the underwear bomb that failed to detonate aboard a jetliner over Detroit on Christmas 2009. This new bomb also was designed to be used in a passenger’s underwear, but this time al-Qaida developed a more refined detonation system.

U.S. officials sought to reassure the public that security measures at airports are strong. They said there are no immediate plans to subject airline passengers to new security screenings.

“I think people getting on a plane today should feel confident that their intelligence services are working, day in and day out,” John Brennan, the top counterterrorism adviser to President Barack Obama, said today on ABC’s “Good Morning America.”