The terrorism threat against the United States has evolved, with homegrown terrorists and a greater diversity in the scope and methods of attack making it more difficult to prevent them, top security officials told a Senate committee Wednesday.
"It is diversifying in terms of sources; it is diversifying in terms of tactics," Homeland Security Secretary Janet Napolitano told the Senate Homeland Security and Governmental Affairs Committee. "The results of these changing
tactics are fewer opportunities to detect and disrupt plots."
The hearing focused on the terrorism threat in the nine years since the September 11, 2001 attacks by al Qaeda on the United States.