Although American intelligence agencies conclude that Al-Qaeda has sought to recruit and train individuals to attack the United States, the FBI has not identified any "sleeper agents" of Osama bin Laden's network in this country so far.

A secret FBI report obtained by ABC News says that Al-Qaeda's capability to hit the United States is unclear.

The conclusion seems to differ from testimony given by FBI Director Robert Mueller, who warned in the past that several sleeper cells were probably in place.

"Our greatest threat is from al Qaeda cells in the United States that we have not yet been able to identify," Mueller said at a hearing in February 2003.

Source: Xinhua