Officials say the move is not due to any specific or credible threats planned against the U.S. They say al Qaeda has previously focused on attacks on anniversary dates, so the military wants to be prepared.
President Barack Obama held a meeting Tuesday in the White House Situation Room with senior members of his homeland security team to ensure that all necessary measures and precautions are being taken in advance of the 9/11 anniversary, said spokesman Jay Carney.
Also, materials seized at the compound where Osama bin Laden was killed mentioned the 9/11 anniversary.
The Associated Press contributed to this report.