WASHINGTON — The CIA takedown of an Al Qaeda plot to blow up a U.S.-bound airliner involved an international sting operation with a double agent tricking terrorists into handing over a prized possession: a new bomb purportedly designed to slip through airport security.

U.S. officials Tuesday described an operation in which Saudi Arabia’s intelligence agency, working closely with the CIA, used an informant to pose as a would-be suicide bomber. His job was to persuade Al Qaeda bomb makers in Yemen to give him the bomb.

After weeks operating undercover in Yemen, the double agent arranged to deliver the device and a trove of vital intelligence to U.S. and other authorities waiting in another country, officials said. He is now safely out of Yemen.

Experts are analyzing the device at the FBI’s bomb laboratory at Quantico, Va., to determine whether it could evade current security systems. Officials said it appears to have a more advanced triggering device than that of the so-called underwear bomb that fizzled instead of exploding aboard a packed passenger jet over Detroit on Christmas Day 2009.


U.S. officials said President Obama was informed of the bomb in early April and was assured that it did not pose a threat to the public. Officials emphasized that the terrorists had not chosen a target or purchased air tickets, and that the plot to blow up an airliner never reached the operational stage.

Like the earlier bomb, the new device bears the forensic signature of top-ranking Al Qaeda bomb maker Ibrahim Hassan Asiri, who was born in Saudi Arabia and is believed to be hiding in Yemen. The double agent apparently never got close to Asiri, and the terrorist network’s master bomber remains one of the top CIA targets.

Officials said the U.S.-Saudi counter-terrorism operation helped authorities finally track Fahd Mohammed Ahmed Quso, who recently became operations manager of Al Qaeda in the Arabian Peninsula, the Yemen-based faction that intelligence officials say poses the greatest danger to the United States.

Quso had been on the FBI’s most wanted list for the bombing of the guided-missile destroyer Cole in a Yemeni port in 2000, which killed 17 U.S. sailors. The FBI had offered a $5-million bounty for information leading to his capture.


On Sunday, a CIA drone aircraft fired a missile that Yemeni officials say killed Quso as he stepped out of his car in a remote valley in southern Yemen. It is not far from where another CIA drone killed Quso’s predecessor, American-born Al Qaeda member Anwar Awlaki, in September.

Sunday’s drone strike and the scheme to steal Al Qaeda’s latest bomb “are part of the same operation,” said Rep. Peter T. King (R-N.Y.), chairman of the House Committee on Homeland Security.

The precise link remains unclear, but U.S. officials say the fact that a friendly intelligence service controlled the supposed suicide bomber, as well as the bomb, meant there was no active plot to bring down a U.S. airliner, even if that was Asiri’s intention.

Some lawmakers briefed on the closely guarded operation warned, however, that Asiri and his assistants may have built copies or other versions of the new bomb, and that other plots may be underway.


“The obvious question right now is, how many more of these bombs are out there?” said Rep. Michael McCaul (R-Texas), a member of the homeland security committee. “They don’t usually build just one; they build multiple.”

Al Qaeda’s bomb makers in Yemen are given prominence in the newest issue of the group’s Web-based English-language propaganda magazine, Inspire. The magazine says militants upgraded their laboratory after seizing supplies from military depots in towns that Al Qaeda recently captured in Yemen’s civil conflict.

An article in the issue, which appeared last week, said earlier bombs were built in a “very modest and small laboratory in a rural area.”

“The modest lab has transformed into a modern one,” the article says. “Especially after [Al Qaeda in the Arabian Peninsula] obtained a large deal of chemicals from military laboratories after they conquered Zinjibar and other cities and towns in the south of Yemen.


“Hence, no wearisome measures are taken anymore to attain the needed large amount of chemicals for explosives,” the article said.

The device and the plot illustrate why Yemen has become a focus of growing concern for U.S. national security officials. Fearful that Al Qaeda may be trying to acquire a new haven from which to launch attacks on the West, the U.S. military and CIA have stepped up counter-terrorism operations there, including the expanded use of armed drones.

U.S. intelligence officials had planned to keep the bomb sting secret, a senior official said, but the Associated Press learned of the operation last week. The AP delayed posting the story at the request of the Obama administration, but then broke the news Monday.

“When the AP got it and started talking about it, it caused all kinds of problems with the operation,” said a U.S. official who would not be quoted by name discussing the classified operation. “The investigation never went to its full conclusion.”


AP spokesman Paul Colford said the news agency held off publishing until U.S. officials told the AP that security concerns were allayed.

“We were told on Monday that the operation was complete and that the White House was planning to announce it Tuesday,” he said.

The disclosure that a double agent had infiltrated an Al Qaeda bomb cell in Yemen, which was first reported by ABC News, could endanger future counter-terrorism operations, U.S. officials said.

“This really puts us in a tough place operationally,” said another official not authorized to speak publicly about intelligence matters.


It’s not clear whether airport body imaging machines now in use would have detected the latest bomb, said Rep. Adam B. Schiff (D-Burbank), a member of the House Intelligence Committee.

“This was a very big success story that involved a lot of hard work and a lot of skill and some luck,” he said. “It’s the part that luck plays that concerns me, because we can’t always count on luck.”

ken.dilanian@latimes.com

brian.bennett@latimes.com