The White House said on Monday that President Barack Obama has learnt in April of an al-Qaeda affiliate's foiled plot to blow up a U.S.-bound airliner.
The White House National Security Council spokeswoman Caitlin Hayden said Obama had also been assured that the device did not pose a threat to the public.
"The president thanks all intelligence and counterterrorism professionals involved for their outstanding work and for serving with the extraordinary skill and commitment that their enormous responsibilities demand," said Hayden.
She also noted that Obama directed agencies "to take whatever steps necessary to guard against this type of attack" and had been regularly briefed by his national security team.
U.S. counter-terrorism officials said U.S. international intelligence agencies foiled an attempt by al-Qaeda's affiliate in Yemen to destroy a U.S.-bound airliner one year after the killing of Osama bin Laden, CNN reported on Monday.
The plot involved an upgrade version of the underwear bomb that failed to detonate aboard a jetliner over Detroit on Christmas 2009. This new bomb was also designed to be used in a passenger's underwear, but contained a more refined detonation system, U.S. officials said. The suspect had not picked a target or bought a plane ticket when stopped and caught by CIA.
A counter-terrorism official told CBS News that the bomb was designed to avoid detection at metal detectors.
Details about the plot suspect and the device are not immediately clear.
Following the media report, the Federal Bureau of Investigation (FBI) and the Department of Homeland Security acknowledged the seizure of an improvised explosive device (IED) designed to carry out a terrorist attack on Monday.
The FBI said it is currently in possession of the explosive device and conducting technical and forensics analysis on it. "Initial exploitation indicates that the device is very similar to the IEDs that have been used previously by al-Qaeda in the Arabian Peninsula in attempted terrorist attacks."
But the FBI stressed that the device "never presented a threat to public safety", and the U.S. government is working closely with international partners to address the issue.
Both the White House and the Department of Homeland Security have said they knew no al-Qaeda threats against the country around the anniversary of the killing of bin Laden.
"At this time, we have no credible information that terrorist organizations, including al-Qaida, are plotting attacks in the U.S. to coincide with the anniversary of bin Laden's death," White House press secretary Jay Carney said on April 26.
The Department of Homeland Security also assured the public last week that it has no indication of "any specific, credible threats or plots against the U.S." tied to the anniversary of bin Laden's death.