The director of the U.S. Federal Bureau of Investigation says
U.S.-based violent extremists have posed a growing national security
challenge since the September 11, 2001 terrorist attacks.
Robert Mueller told a Senate Homeland Security Committee hearing
Wednesday that homegrown terrorists are particularly difficult to
detect, since they lack formal ties to recognized groups.
The FBI chief said threats also come from self-directed groups linked to terrorist organizations through money or training.
He said in recent months authorities have disrupted a number of
homegrown plots at various points in planning -- from casing out
targets to gathering explosives and readying to strike.
He cited as an example the plot that emerged last week in which
individuals in Denver and New York City were allegedly conspiring to
bomb U.S. targets.
Mueller said the FBI does not believe there is an imminent threat
related to the case, which involves Afghan immigrant Najibullah Zazi.
Prosecutors allege the 24-year-old received explosives training from al-Qaida in Pakistan.
Homeland Security Secretary Janet Napolitano said recent incidents have
shown the threat of terrorism can come from people in many different
areas of the country, with a broad range of backgrounds.
Napolitano testified that her department is working to build up the
nation's terrorism defense by strengthening federal cooperation with
state and local law enforcement.
She said homeland security officials also do outreach with Arab, Somali
and Muslim communities in the United States to prevent the alienation
thought to breed extremism.