The holiday travel season has passed without an attack, but the Homeland Security Department says the danger is still high.
The department is keeping the national terror alert level at orange, the second-highest threat status.
A spokeswoman says the Homeland Security department has information that warrants remaining at a heightened state of alert.
A U.S. intelligence source says a network of analysts is comparing data from different sources to see if militants are spreading "disinformation."
U.S. officials haven't identified any specific threats, but have passed on information that led to cancellations and delays of plane flights.