WASHINGTON (AP) - Senior U.S. officials say there's no evidence that anyone linked to al-Qaida has entered the country to carry out an attack on the 10th anniversary of the Sept. 11 attacks.
The officials insisted on anonymity to discuss the investigation.
Police and FBI agents remain on alert as investigators look for proof of a plot against Washington or New York.
Since late Wednesday, counterterrorism officials have chased a tip that al-Qaida may have sent three men to detonate a car bomb. At least two of those men could be U.S. citizens.
By Saturday, there was still no intelligence backing that up and officials continued to question the validity of the initial tip.