US airlines deny receiving specific warnings about al-Qaida attack

American airlines and airports say they weren't warned before September 11 of any specific hijacking threat.

The Federal Aviation Administration says it warned airlines and airports that terrorists might be planning hijackings at the end of July.

But pilots' and flight attendants' unions say their members were never told.

Condoleezza Rice, the president's national security adviser, says the airlines were asked to "use caution".

The FAA declined to release copies of the classified warnings, which are sent to airline security directors or posted on a secure Web site.

In a written statement, American Airlines says it "received no specific information from the US government advising the carrier of potential terrorist hijacking in the United States in the months prior to September 11."