Sources: Al Qaeda may have made contact in U.S. recently
U.S. officials say al Qaeda info is dated but had been updated recently.
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WASHINGTON (CNN) -- Intelligence found in Pakistan suggests that suspected al Qaeda operatives in that country contacted an individual or individuals in the United States in the past few months, according to two senior U.S. government sources.
The officials would not characterize the nature of the communication.
But the sources said other information from Pakistan has prompted investigations in the United States to uncover whether there are any individuals or terrorist cells plotting an attack on U.S. soil.
In addition, two senior Pakistani intelligence sources told CNN that there is evidence at least six individuals in the United States were contacted by Muhammad Naeem Noor Khan, an alleged al Qaeda operative who was recently taken into custody in Pakistan. U.S. officials have not confirmed that information.
White House press secretary Scott McClellan told reporters Aboard Air Force One that two intelligence streams "came to light more fully" last Friday. The first dealt with Khan and the other dealt with an undisclosed threat.
"I can't go further into it because it could compromise some ongoing operations at this point," McClellan said.
He noted, "When you connect all these streams of intelligence, it paints an alarming picture."
Without mentioning Khan by name, McClellan said the suspected al Qaeda operative "had computer files with very detailed and specific information about some of al Qaeda's intentions."
"This is an active al Qaeda operative who we know has ties to other al Qaeda operatives who are involved in plotting to carry out attacks against the American people," McClellan said.
It was Khan's arrest and documents in his possession that sparked this week's increased threat levels in Washington, New Jersey and New York, U.S. officials said. (Full story)
Khan is a computer expert suspected of helping Osama bin Laden communicate with his terror network, U.S. government sources said. Pakistani officials said the man's identity cannot be confirmed because he has used multiple aliases.
U.S. sources said Khan told interrogators al Qaeda uses Web sites and e-mail addresses in Turkey, Nigeria and tribal areas of Pakistan to pass messages among themselves.
Couriers were often used to deliver computer discs, and the suspect would then post the messages on Web sites, but only briefly, the sources said.
According to the sources, after messages were sent and read, the files were deleted.
E-mail addresses were used only two or three times; if the information was really sensitive, an address might be used only once.
The U.S. sources allege Khan assisted in the evaluation of potential targets and served as a "clearinghouse" of information. He told investigators that he does not know where bin Laden is hiding, the sources said.
They said Khan's father facilitated a lot of his international travel, but they do not think the father knew what his son was doing.
Much of the surveillance of possible terror targets in the three U.S. cities took place before September 11, 2001, but there was an indication of reconnaissance updates as recently as January, Bush administration officials said Tuesday.
"We know from the way al Qaeda does business, including on the 9/11 attacks, that they do their homework well in advance, then they update it just before they launch an attack," said Frances Fragos Townsend, a homeland security adviser to President Bush.
U.S. Homeland Security Secretary Tom Ridge said some of the information was updated earlier this year but that "there's no evidence of recent surveillance."
Neither Ridge nor Townsend said how much information was updated in January.
A senior military U.S. official said a computer seized from Khan contained hundreds of images, including photographs, drawings and layouts of various potential U.S. targets. (Full story)
Some of the photos were years old, while others had been taken as recently as the past few months, the official said. Some images showed underground garages, leading to the conclusion those areas had been under surveillance.
But the information did not include details of any specific plot or time.
"These reports are extraordinarily detailed," Townsend said. "These individuals clearly had access; they were inside this country, inside these targets, crawling all over them, making sure they understood those buildings."
Pakistani 'breakthrough' touted
In Britain, police questioned 12 men Wednesday on suspicion of being involved in terrorist activities. They were arrested Tuesday as a result of information that Pakistani authorities said they shared with their British counterparts.
British police declined to confirm how they learned of the dozen suspects, but senior Pakistani intelligence officials said Khan told interrogators that there was a terror cell in Britain and that he frequently relayed messages from Pakistan to its leader.
The Pakistani officials said the leader described by Khan was among those arrested in Britain. Scotland Yard has said the arrests were part of a "preplanned, ongoing intelligence-led operation."
Pakistani Information Minister Rashid Ahmad said that Pakistani security forces also had captured "valuable people" who provided "valuable information."
"It is a great achievement of our security forces," Ahmad said. "It is a great breakthrough in the al Qaeda network."
Ahmad would not reveal any other information, saying it was "best not to say too much."
Ahmed Khalfan Ghailani -- a Tanzanian arrested in Pakistan last week in connection with al Qaeda's bombings of U.S. embassies in East Africa in 1998 -- also provided "very important" information, Ahmad said Monday.
In addition, a senior Pakistani intelligence official said seven more suspected al Qaeda members have been taken into custody since Ghailani's arrest -- including one who was trying to leave the country Monday.
CNN's Kelli Arena, Kevin Bohn, Syed Mohsin, Syed Naqvi and Barbara Starr contributed to this report.