WASHINGTON, 7 March 2003 — The recent arrest of a top Al-Qaeda operative has confirmed for US law enforcement the identities of about a dozen suspected terrorists in this country, a government official said yesterday.

Discussing the intelligence haul from the search of Khalid Shaikh Mohammed’s living quarters, this official said that authorities had known about the individuals whose names were part of the intelligence haul.

Federal law enforcement officials had said earlier that a vast amount of information was found when Mohammed was arrested at a home in Pakistan on Saturday, including computers, computer disks, portable telephones and documents.

The official yesterday said authorities are keeping the Al-Qaeda suspects under surveillance and that no arrests appear to be imminent. Continued tracking of the suspects might lead authorities to other Al-Qaeda figures, the official said.

On Wednesday, the FBI warned that while the arrest was a major blow to Al-Qaeda, it could speed up planned attacks by the terrorist network in the United States.

Mohammed’s capture “deals a severe long-term blow” to Al-Qaeda’s ability to carry out attacks, said a weekly FBI memo sent to 18,000 state and local law enforcement agencies. “However, in the short term, the apprehension may accelerate execution of any operational planning already under way,” the bulletin said.