"Double agent" foiled al-Qaeda bomb plot The bomber recruited by the Yemen branch of al-Qaeda to blow up a US airliner was actually a double agent working for US and Saudi intelligence, a US official briefed on the case said on Tuesday. The agent, who works for Saudi intelligence, infiltrated the group and volunteered for the suicide mission, which was foiled last month but was made public on Monday. The revelation appears to be a major intelligence coup for the US and its partners at a time when officials say that al-Qaeda has been significantly weakened but that its affiliates are still planning attacks on the US mainland. The plan involved a device believed to be a sophisticated bomb without any metallic parts and was a more advanced version of the so-called "underwear bomb" that failed to detonate on a flight from Amsterdam to Detroit in December 2009. The information about the double agent was first reported by the Los Angeles Times, which said that he had handed over the device to US and other authorities and was now being debriefed in a third country. The FBI was examining the device at its bomb laboratory to see if it would have evaded airport security systems, the paper said. Investigators were also looking to see if the bomb bore the forensic trace of Ibrahim Hassan Asiri, the al-Qaeda bomb-maker believed to be in Yemen. "We're trying to understand different aspects of the design to make sure that we're able to take preventative action in the future," said John Brennan, the White House's counterterrorism adviser, in a television interview on Tuesday. US authorities said on Tuesday that security procedures at the country's airports remained unchanged, but given the furore over the new body scanners introduced at US airports in the wake of the attempted 2009 attack, any further security procedures would likely prompt a political backlash. "I would not expect any real changes for the travelling public," said Mike Rogers, chair of the House intelligence committee. Speaking 10 days ago, senior US intelligence officials said that "core" al-Qaeda had been so weakened that it was incapable of organising a 9/11 style attack, but that some if its affiliates, especially Yemen-based al-Qaeda in the Arabian Peninsula (AQAP), remained a potent threat. "Each [affiliate] will seek opportunities to strike western interests in its operating area," said Robert Cardillo, deputy director at the Office of the Director of National Intelligence. Peter King, chair of the House homeland security committee, said he had been told by administration officials that information from the bomb plot had been used in a US drone attack in Yemen on Sunday. The Yemeni government said that the attack killed Fahd Mohammad Ahmed Al-Quso, best known for masterminding the bombing of the USS Cole ship in 2000 and who was also believed to be the architect of the new foiled bomb plot.