WASHINGTON (CNN) -- Citing credible threats that al Qaeda might be planning attacks on American targets, the U.S. government Friday raised the national color-coded threat level to orange, indicating a high risk of terrorist attacks.
The change is only the second time the alert level has risen above yellow, or an elevated risk, since the September 11 attacks.
"This decision for an increased threat designation condition is based on specific intelligence received and analyzed by the full intelligence community," Attorney General John Ashcroft said. "This information has been corroborated by multiple sources."
In addition, the Joint Chiefs of Staff are expected to raise security measures at U.S. military bases across the United States by the end of the day Friday.
"There is a large spike in threat reporting that shows al Qaeda cells are possibly close to ready to launch attacks," a senior U.S. military official said.
Ashcroft cited recent reports that al Qaeda cells are "still determined to attack Americans" and could be planning strikes coinciding with the Hajj pilgrimage to Mecca, Saudi Arabia, as well as recent arrests in Europe of suspected terrorists allegedly planning chemical attacks.
"Recent reporting indicates an increased likelihood that al Qaeda may attempt to attack Americans in the United States and/or abroad in or around the end of the Hajj, a Muslim religious period ending mid-February 2003," Ashcroft said.