The Pentagon said Wednesday it has raised the alert level at military bases in the United States as a precaution before the 10th anniversary of the 9/11 attacks.
"This is not in response to any particular threat but is a prudent and precautionary measure," said Pentagon spokesman George Little.
“This is not in response to any particular threat, but is a prudent and precautionary measure.”
Al-Qaeda has “focused on holidays and milestone events in the past” and the 10-year anniversary of 9/11 “was mentioned in the documents seized” in the US raid in May that killed Osama bin Laden at his Pakistani compound, he said.
The Pentagon said the move takes effect on Wednesday and will continue through Sunday.
The decision was taken by Defense Secretary Leon Panetta on the recommendation of the head of US Northern Command, General Charles Jacoby, who oversees forces in North America, Little said.
The Pentagon declined to divulge the details of the new security level or what measures that might require at bases in the continental United States.
Most US bases abroad were already operating under a heightened alert level, Little said.
Homeland Security Secretary Janet Napolitano has said there is “no specific or credible intelligence” that Al-Qaeda or its affiliates are plotting an attack linked to the anniversary of the worst terror strikes on US soil.
But Napolitano said the government has adopted an enhanced state of “vigilance” ahead of the anniversary and officials said the Pentagon's move was in keeping with that approach.
US counter-terrorism efforts underwent a thorough overhaul after September 11, 2001, when nearly 3,000 people were killed in New York, Washington and Pennsylvania.
US security is expected to be tight this Sunday for the anniversary, when President Barack Obama attends ceremonies at the three sites where the terrorists struck: the 'ground zero' site in Manhattan where the World Trade Center stood; the Pentagon outside Washington; and Shanksville, Pennsylvania, where a hijacked United Airlines jet crashed after passengers and crew fought back.
Napolitano also has said America now faces less risk from a repeat massive terror strike than from a smaller, less deadly hit which could prove harder to detect.