Mueller warned a White House committee that al Qaeda is still intent on high-profile attacks.
"Al Qaeda is decentralised but the group is committed to high profile attacks against the west," he cautioned.
According to a newspaper, a sting operation in Yemen involving an undercover agent named Ibrahim Hassan al-Asiri, who was working for Saudi Arabian intelligence and the CIA led to the discovery of the bomb device, which was handed over to western intelligence.
It is now being examined by FBI experts at its forensic labs in Quantico, Virginia.
Al Asiri is a leading bombmaker from the Arabian Peninsula, whose talent for making hard-to-detect bombs is emerging as a major focus of western counter-terrorism measures. He is thought to have survived a US drone attack last year.
The capture of the latest underwear bomb has prompted security concerns across the US that al Qaeda and its allies are still actively trying to launch a high profile attack on US soil. Mueller said that such militants remained the "top" terrorist threat to the nation.
Washington: Federal Bureau of Investigation (FBI) Director Robert Mueller has urged the US government for renewal of surveillance measures after a device from al Qaeda’s leading underwear bombmaker was discovered.
First Published: Thursday, May 10, 2012, 13:46