The CIA reportedly has stopped another plot by al Qaeda to take down a U.S.-bound airliner with an underwear bomb.

The device was a sophisticated new design that was set to go off around the first anniversary last week of the killing of Osama bin Laden, the Associated Press reports.

The plan was an upgraded version of the underwear bomb that failed to detonate aboard a jetliner over Detroit on Christmas 2009.

The new bomb was also designed to be used in a passenger's underwear, but this time al Qaeda developed a more refined detonation system, according to U.S. officials.

While the FBI is said to be examining the explosive material to see whether it could have successfully passed through airport security and gotten onto a plane, it reportedly did not contain metal and would evade metal detectors.

It's still unclear whether new body scanners used in many airports would have detected it.

According to the AP, 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.

The terror bust comes after the White House and Department of Homeland Security said there were no known al Qaeda plots around the bin Laden anniversary.

We have no credible information that terrorist organizations, including al Qaeda, are plotting attacks in the U.S. to coincide with the anniversary of bin Laden's death, White House press secretary Jay Carney told the AP on April 26.

On May 1, the Department of Homeland Security told the AP, We have no indication of any specific, credible threats or plots against the U.S. tied to the one-year anniversary of bin Laden's death.

The AP learned of the foiled underwear bomb plot last week but agreed to White House and CIA requests not to reveal it immediately because the sensitive intelligence operation was still under way. Once officials said those concerns were allayed, the AP decided to disclose the plot Monday despite requests from the Obama administration to wait for an official announcement Tuesday.