Within minutes of President George W Bush giving 48-hour ultimatum to President Saddam Hussein, the US raised its terrorism alert from "elevated" to "high."
The security around sensitive sites, including tunnels and bridges, was put on high alert in response to intelligence reports warning terror attacks.
The Department of Homeland Security said a large volume of reporting across a range of sources indicated that Al Qaeda probably would attempt to launch terrorist attacks against US interests claiming they were defending Muslims or the Iraqi people rather than Saddam Hussein's regime.
The department said there were many recent indications that Al Qaeda is planning attacks using chemical, biological and
radiological materials.
