Three international air carriers have grounded flights between Europe and the United States because of new security concerns.
British Airways and Air France each cancelled two Washington-bound flights, scheduled for today (Sunday) and Monday.
The British carrier also scrubbed a flight from London to Miami (Florida). In addition, U.S.-based Continential Airlines grounded its flight (today) from Glasgow, Scotland, to Los Angeles.
Return flights were also cancelled. A spokeswoman for the British carrier says flights were grounded on the advice of the British government.
The U.S. Department of Homeland Security said it has shared new intelligence with Britain, France and other foreign governments about a possible plot by the al-Qaida terror network to target passenger planes.
A U.S. security official called the information "specific" and "credible," but did not provide details.
The Washington Post (newspaper) reports the threat may have involved a release of chemical or biological agents aboard a passenger plane or the transport of a radiological device.
The New York Times (newspaper) says that if today's flights had taken off, U.S. officials considered sending biological and chemical teams to screen the planes on their arrival.
Homeland security officials say there are no plans to raise the U-S terror threat level.
The United States raised its terror threat level to "high" in late December, and terrorism concerns led to international flight cancellations and delays by British Airways, Air France and other airlines. The threat level was lowered to "elevated" early this month (January 9th).
The latest security concerns again raised fears that more September 11th-style terrorist attacks on the United States are possible. Four commercial aircraft were seized by hijackers, who crashed three of the planes into New York City and the nation's capital. The attacks were blamed on the al-Qaida terrorist network led by Osama bin Laden.