Al Qaeda arrests yield 1,000 disks
The UK hints at tensions with the U.S. over how much information to make public about terrorist threats.
Islamabad says an important counterterror operation has been compromised by Washington.
A tip from a terror suspect held in Pakistan may have led to at least one of the 12 terror suspects arrested in Britain.
WASHINGTON (CNN) -- Nearly 1,000 computer disks were recovered last week as part of a series of arrests in the United Kingdom of alleged al Qaeda operatives, U.S. government sources have told CNN.
Both British and American authorities are analyzing the information in the disks for any potential clues to possible al Qaeda attack plans.
Among those arrested last Tuesday were Esa al-Hindi, who is described by U.S. officials as a senior al Qaeda operative and someone who personally conducted surveillance in 2000 and 2001 of buildings in New York and New Jersey.
A law enforcement source told CNN there was an intense search going on in the New York area for anyone al-Hindi and two associates, who allegedly did reconnaissance with him, may have met while in the United States.
Officials said they are investigating whether Muhammad Naeem Noor Khan, recently arrested in Pakistan, also visited the United States to do reconnaissance.
So far, they said, there is no proof but they are not ruling it out.
Information gathered from the arrest of Khan, a suspected al Qaeda operative, led to the arrests in Britain, Pakistani officials have said.
Meanwhile, the effort by U.S. officials to justify raising the terror alert level last week may have shut down an important source of information that has already led to a series of al Qaeda arrests, Pakistani intelligence sources have said.
Until U.S. officials leaked the arrest of Khan to reporters, Pakistan had been using him in a sting operation to track down al Qaeda operatives around the world, the sources said.
In background briefings with journalists last week, unnamed U.S. government officials said it was the capture of Khan that provided the information that led U.S. Homeland Security Secretary Tom Ridge to announce a higher terror alert level.
The unnamed U.S. officials leaked Khan's name along with confirmation that most of the surveillance data was three or four years old, arguing that its age was irrelevant because al Qaeda planned attacks so far in advance.
Law enforcement sources said some of the intelligence gleaned from the arrests of Khan and others gave phone numbers and e-mail addresses that the FBI and other agencies were using to try to track down any al Qaeda operatives in the United States.
Then on Friday, after Khan's name was revealed, government sources told CNN that counterterrorism officials had seen a drop in intercepted communications among suspected terrorists.
Officials used Sunday's talk shows to defend last week's heightened alerts, amid widespread claims the White House disclosed Khan's arrest to justify raising its terror alert level. (Full story)
Pakistan's Information Minister Sheikh Rashid Ahmad downplayed the effect of the U.S. "outing" of Khan, saying Islamabad is looking forward and not back.
"We are moving towards the positive side," he said. "We've got positive information and we believe there will be positive results."
Pakistan continued its crackdown over the weekend, going after multiple al Qaeda cells around the world.
They are on the manhunt for two North African al Qaeda operatives -- Abu Farj of Libya and an Egyptian named Hamza -- who are connected to Ahman Khalfan Ghailani, who was arrested in late July.
Meanwhile, an al Qaeda operative believed to have been close to bin Laden and Taliban leader Mullah Mohammed Omar was flown home to Pakistan after he was arrested in Dubai, intelligence sources said. (Senior figure arrested)
Pakistani intelligence officials said information provided by Khan not only contributed to the rise in the U.S. terror alert level but also led to 13 arrests on terrorism charges in Britain.
Four of the 13 have since been released, but British police have been given until Tuesday to question the remaining nine. (Full story)
British officials declined to comment.
CNN Justice Correspondent Kelli Arena and correspondent Maria Ressa contributed to this report