President Barack Obama's top counterterrorism adviser expressed concern Tuesday over the growing threat of "small-scale attacks," citing recent foiled plots aimed at New York City.
John Brennan pointed to the cases of Najibullah Zazi, an Afghan immigrant who has admitted to planning an attack on New York's subways, and Faisal Shahzad, a Pakistani-American suspected of planting a malfunctioning car bomb in Times Square, as part of a trend toward less spectacular assaults.
"These are the ones I am concerned about," Brennan said during a forum sponsored by The Nixon Center.
Brennan also confirmed that newly-created US interrogation teams designed to question terror suspects started operating at home and abroad "over the past six, seven months or so."
The teams helped interrogate Shahzad, who appeared in court for the first time on Tuesday, and took part in more abbreviated sessions with Umar Farouk Abdulmutallab, the Nigerian charged with trying to blow up a Detroit-bound passenger jet with explosives stitched in his underwear.
The elite teams are drawn from intelligence agencies, law enforcement and the Defense Department, and include experts with linguistic skills, knowledge of a particular region or terror network, as well as specialists in "behavioral science," according to senior administration officials.
Brennan's comments appeared aimed at defusing criticism of the White House over how it has questioned and prosecuted terror suspects.
The Obama administration came under fire after the director of national intelligence, Dennis Blair, told lawmakers in January that the special interrogation teams were not yet operational, despite a decision to form the teams months earlier.
Obama approved establishing the high-value interrogation group, or HIG, in August as part of a larger effort to break with the previous administration and overhaul how terror suspects are questioned and prosecuted.
The interrogation group is led by an official from the Federal Bureau of Investigation, with deputies from the Central Intelligence Agency and the Defense Department, and reports to the National Security Council.
The change asserts more direct White House control over interrogations that had been dominated by the CIA and plagued by controversy and allegations of torture and abuse.
CIA officers in the interrogation teams are not expected to take part directly in questioning of suspects on US soil, officials said.
Although no law bars intelligence officers from participating in the interrogations in the United States, the spy agency as a rule has chosen to play a supporting role to avoid being drawn into a possible court case if a suspect is prosecuted, officials said.