The threat, said to involve potential car bombs, would target New York City or Washington, D.C., sources said. Authorities have obtained what they believe is information on possible suspects tied to central Al Qaeda, but they have not necessarily determined names of possible suspects.
"As we know from the intelligence gathered from the [bin Laden] raid, Al Qaeda has shown an interest in important dates and anniversaries, such as 9/11," Department of Homeland Security spokesman Matt Chandler said in a written statement. "In this instance, it's accurate that there is specific, credible but unconfirmed threat information."
According to a senior U.S. official with knowledge of the threat, "People are aggressively pursuing leads,” and it is "specific enough to elicit worry." Another senior U.S. official stressed the threat is still “unconfirmed” so it is being chased down and investigated. It was identified in intelligence received from overseas.
President Obama has been briefed on the seriousness of this threat, according to a senior administration official
"It feels more than aspirational," one official said.
The FBI and Department of Homeland Security were drafting a bulletin Thursday night to send to local law enforcement across the country.
"We have a duty to warn,” the senior U.S. official said.
U.S. officials have been saying for days that there is no known credible threat related to the anniversary. But when asked Thursday by reporters whether that’s still the case, Homeland Security Secretary Janet Napolitano seemed to at first hesitate.
Then she said:
"It is still the case that we don't have something that would reach that standard, but we still have lots of chatter out there. And we take every bit of that seriously and track it down. ... The date is important because it's 9/11. But as I said, in the intel world there's lots of chatter and we're taking it all seriously. Should there be something that rises to the level where I have to issue a threat advisory, we will issue a threat advisory."
There were documents found inside Usama bin Laden's compound in Abbottabad, Pakistan, that mentioned aspirations to strike on the 10th anniversary of the 2001 attacks.