The government acted Saturday to make American commercial airplanes less vulnerable to terrorists, requiring visas for people from most countries when they travel through the United States from one foreign airport to another.
The government suspended two programs that allowed foreigners to stay in U.S. airports without visas while awaiting flights to other countries.
The State Department said Al Qaeda (search) and other terrorism organizations had planned to use the programs to get access to flights to and from the United States.
The lack of screening for visas could have allowed potential terrorists to enter the country without being checked against federal lists of terrorism suspects.
The action by the departments of State and Homeland Security (search) was effective at 11 a.m. EDT Saturday.
The departments "have received specific, credible intelligence ... that certain terrorist organizations including Al Qaeda have identified the visa and passport exemptions of those programs as a means to gain access to aircraft en route to and from the United States," State Department spokeswoman Jo-Anne Prokopowicz said.
She said the intelligence included information from both the FBI and the CIA.
The announcement said the suspension would be in effect for at least 60 days, during which public comment would be solicited. Both departments want to reinstate the programs quickly, it said, but current intelligence will be a factor on lifting the suspensions.
The suspension does not affect passengers from 27 "visa-waiver" countries, mostly in Europe and the Far East and Southeast Asia.
Those most affected, who will no longer be granted visa-free entrance for airport layovers, are passengers from Brazil, Mexico, South Korea, the Philippines (search) and Peru.
Hardest hit airports are the international airports in Los Angeles, Miami, New York, Dallas and Houston.
Sen. Hillary Rodham Clinton (search), D-N.Y., had complained to Homeland Security Secretary Tom Ridge last week about the potential for someone without a U.S. visa "to take a flight from a country with less-stringent security to a U.S. airport and possibly roam that U.S. airport during a layover."
Even for airports that isolate such passengers in secure areas, she wrote, "it is extremely discomforting knowing that this is the most security that could be imposed on a possible terrorist."
Ridge said in a statement Saturday that the suspensions, "while aggressive, are an appropriate response to the threat. We know they will have an impact on international travelers, but we believe they are necessary in order to protect lives and property."
Airlines were instructed to stop allowing layovers by travelers under the transit-without-visa or the international-to-international transit programs.
Homeland Security agencies also were acting to increase security at airports and on airplanes that normally carry and process passengers under the programs, the statement said.
The suspensions will hit both U.S. airlines and airports.
"My feeling generally is that although this will be an inconvenience to passengers and could be financially harmful to airlines and airports, if we need to do this for security reasons, then we should do it," David Stempler, president of the Air Travelers Association, said.
U.S. commercial aviation still has not recovered from the Sept. 11, 2001, terror attacks.
In the year that ended Sept. 30, 2001, the programs brought 1.6 million travelers through U.S. airports en route to foreign destinations. For the budget year that ended last Sept. 30, the total was 614,519.
American Airlines, which carried 93,328 passengers in 2002 under the 51-year-old transit-without-visas program, is the airline most severely affected. Spokesman Carlo Bertolini would say only: "We comply, and we will continue to comply, with all federal security directives."