The CIA thwarted an ambitious plot by Al Qaeda's affiliate in Yemen to destroy a U.S.-bound airliner using a bomb with a sophisticated new design around the one-year anniversary of the killing of Osama bin Laden, U.S. officials said.

An image of the old underwear bomb.

The plot involved an upgrade of the underwear bomb that failed to detonate aboard a jetliner over Detroit on Dec., 25, 2009. This new bomb was also designed to be used in a passenger's underwear, but this time Al Qaeda developed a more refined detonation system, U.S. officials said.

The FBI is examining the latest bomb to see whether it could have passed through airport security and brought down an airplane, officials said. They said the device did not contain metal, meaning it probably could have passed through an airport metal detector. But it was not clear whether new body scanners used in many airports would have detected it.

The would-be suicide bomber, based in Yemen, had not yet picked a target or bought his plane tickets when the CIA stepped in and seized the bomb, officials said. It is not immediately clear what happened to the alleged bomber.

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