WASHINGTON -- The Department of Homeland Security announced yesterday that it will require all foreign air carriers to place an armed guard on any flight over United States airspace if counterterrorism officials ask them to do so.
The move, described as an "emergency" rules change that is effective immediately, reflects growing concern that the Al Qaeda terrorist network may try to exploit foreign carriers as a gap in US air security by hijacking their planes and flying them into populated areas or high-risk industrial sites.
The policy comes as millions of Americans crowd airports in the busy holiday travel season and less than a week after the French government canceled Christmas flights on Air France between Paris and Los Angeles after US officials shared intelligence indicating Al Qaeda might have been planning to hijack one or more of them.
"We are asking international air carriers to take this protective action as part of our ongoing effort to make air travel safe for Americans and visitors alike," said Homeland Security Secretary Tom Ridge. "I have said that we will take specific steps to increase security whenever necessary, and with this action we are doing just that."
The Bush administration decided to raise the nation's security level to "high" on Dec. 21, citing increased "chatter" in intercepted Al Qaeda communications suggesting that terrorists may be planning a hijacking plot to rival the attacks of Sept. 11, 2001.
Ridge said yesterday he remains as concerned about the possibility of an imminent attack as he was last week and that the orange alert is likely to remain in effect at least through New Year's Eve.
No arrests have been made in connection with the Air France cancellations, Natalie Loiseau, a spokeswoman for the French Embassy in Washington, said yesterday. The incident forced about 1,800 passengers on six flights to reschedule.
By effectively extending the US air marshals program to foreign cargo and passenger carriers that fly to, from, or over the United States, the policy will give officials a third option -- other than doing nothing or canceling the flight -- when ambiguous intelligence signals there may be a problem, security specialists said.
The United States has asked foreign governments to mirror its new security measures, such as the air marshal program, on a voluntary basis, said P. J. Crowley, a former National Security Council official who is now a senior fellow with the Center for American Progress, a liberal think tank. The Air France incident, he said, probably pushed the Bush administration to make that program mandatory.
"In government, you don't normally make major pronouncements in the week between Christmas and New Year's without cause," he said. "Clearly, this is no coincidence. In the Air France incident, an alternative to canceling the flight could have been `let's put a marshal on board to watch the passenger we had concerns about.' That step wasn't taken. And this shows the limitation of voluntary efforts that existed up until Air France. In light of that, we're basically mandating that if we have concerns about a particular international flight, we can direct those carriers to beef up their security."
However, Loiseau said France had begun an "unprecedented" air marshal program even before the Air France incident as a result of conversations with US officials. She declined to say how many French marshals had been trained and were available for service.
Also anticipating the mandate, Britain announced Sunday that it would place armed sky marshals on some of its passenger planes, over the objections of British airline pilots.
The policy will effectively be a tax on travel and trade because its cost will be passed on to consumers and could strain smaller carriers or nations that fly into the United States, said James Carafano, a homeland security specialist with the conservative Heritage Foundation. But he said it was a good idea and could be a valuable additional layer to US defenses so long as the training of the foreign air marshals is adequate.
"If you are going to do these programs, you've got to do it right," he said. "You don't want to just put a guy with a gun on a flight and say, `Don't let anyone hijack the plane.' That's a recipe for disaster. You want people who are very well-trained, well-tested, and regulated."
Ridge said the United States would provide assistance to nations that ask and US inspectors will work "with our international partners to ensure" compliance.
Brian Doyle, a Homeland Security spokesman, said US air marshals must pass a basic nine-week law enforcement training course in Artesia, N.M., then complete a four-week air marshal finishing course in Atlantic City, N.J. There were just 33 air marshals before the Sept. 11, 2001, attacks. Now there are thousands, though the exact number is classifed, as is information regarding which flights are carrying air marshals. Security specialists said high-profile domestic and international US flights are likely to have armed plainclothes marshals on board.
The occupation's quick expansion has resulted in some problems, including delayed background checks. The program recently transferred from the Transportation Security Administration to the Immigration and Customs Enforcement directorate, home to former immigration and customs officials who can add to the air marshals' capacity in a crisis.
Senator Charles E. Schumer, head of the Senate Democratic Homeland Security Task Force, said the policy of mandatory foreign air marshals is a good idea that is long overdue.
"It's good that the administration did this but, given the obvious danger of terrorists using a foreign plane for a 9/11-like attack, it should have asked for air marshals on these flights a year ago," Schumer, a New York Democrat, said in a statement. "The fundamental flaw with the way the administration handles homeland security is that it waits for threats to emerge and then takes steps to defend against them."
Massachusetts Port Authority spokesman Phil Orlandella said Logan International Airport officials had already met to discuss the mandate and no flights had been delayed or canceled because of the requirement.
Ralph Ranalli of the Globe staff contributed to this report.