No New security plans despite plot

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

The CIA, with help from a well-placed 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, US officials said.

Officials said the bomb represents an upgrade over the underwear bomb that failed to detonate aboard a plane over Detroit on December 25 2009. This new bomb was also designed to be used in a passenger's underwear, but this time al Qaida developed a more refined detonation system.

FBI experts are picking apart that non-metallic device to see if it could have slipped through security and taken down a plane.

Meanwhile, US 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 US president Barack Obama, said on ABC television's Good Morning America.

Just last winter, al Qaida's Yemen branch boasted that it had obtained a supply of chemicals used to make bombs. Chemicals can eliminate the need for electrical equipment to detonate explosives.

"Hence, no wearisome measures are taken anymore to attain the needed large amount of chemicals for explosives," the group wrote in its online magazine, "Inspire."

Working with an informant close to al Qaida in Yemen, the CIA caught wind of the bomb plot last month.

The would-be bomber was supposed to buy a plane ticket to the United States and detonate the bomb inside the country, officials said.

Senator Dianne Feinstein, a Democrat, who heads the Senate Intelligence Committee, told reporters on Monday night that she had been briefed about an "undetectable" device that was "going to be on a US-bound airliner".

Before the bomber could choose his target or buy his ticket however, the CIA swooped in and seized the bomb.

The fate of the would-be bomber remains unclear.

The plot was a reminder of the ambitions of al Qaida in Yemen, the most active and dangerous branch of the terrorist group. While al Qaida's core in Pakistan has been weakened over the past decade, instability in Yemen has allowed an offshoot group to thrive and set up training camps there. In some parts of the country, al Qaida is even the de facto government.

Though analysis of the device is incomplete, US security officials said they remained confident in the security systems that were in place.

"These layers include threat and vulnerability analysis, pre-screening and screening of passengers, using the best available technology, random searches at airports, federal air marshal coverage and additional security measures both seen and unseen," Department of Homeland Security spokesman Matthew Chandler said.

"The device did not appear to pose a threat to the public air service, but the plot itself indicates that these terrorists keep trying to devise more and more perverse and terrible ways to kill innocent people," Secretary of State Hillary Rodham Clinton said during a news conference in New Delhi.

It is not clear who built the bomb, but because of its sophistication and its similarity to the Detroit bomb, authorities suspected it was the work of master bomb maker Ibrahim Hassan al-Asiri or one of his students. Al-Asiri constructed the first underwear bomb and two others that al Qaida built into printer cartridges and shipped to the US on cargo planes in 2010.

Both of those bombs used a powerful industrial explosive. Both were nearly successful.