Officials have received a credible but unconfirmed terror threat having to do with New York or Washington.
A counterterrorism official tells The Associated Press that law enforcement officials have been investigating the intelligence since it was received late Wednesday night. The official spoke on condition of anonymity to discuss sensitive security information.
The counterterrorism official says the information in the threat is so specific and comes just days before the 10th anniversary of the 9/11 attacks that it could not be ignored.
Security measures around the country, including in New York and Washington, have been enhanced in the weeks leading up to the anniversary.
Homeland Security Department spokesman Matt Chandler described the threat as specific and credible but unconfirmed. He did not release any information about potential targets.