British Airways Flight 223 from Heathrow to Dulles airport in Washington was once again held at the gate in London as U.S. officials checked the passenger manifest. The flight has been cancelled twice in recent days and delayed several times.
It was the latest instance of the intense scrutiny to which foreign flights are being subjected as part of the orange or "high" terrorist alert in the United States. Some of the intelligence behind that alert suggesting al Qaeda may have planned to take over a foreign flight and use it against an American target.
Several other flights also have been scratched in recent days. Other planes have been searched on arrival in the United States or even escorted to the ground by military fighters. The Homeland Security Department last week began requiring that armed agents be placed aboard incoming flights that U.S. intelligence determines might be threatened.
There are also concerns about a new system for tracking foreigners that is being inaugurated this week.
Under the program, called US-VISIT foreigners entering U.S. airports and seaports from all but 27 nations will have their fingerprints scanned and their photographs taken.
The program will check an estimated 24 million foreigners each year, though some will be repeat visitors.
The only exceptions will be visitors from 27 countries — mostly European nations whose citizens are allowed to come to the United States for up to 90 days without visas.
While most airlines were complying with the U.S. rules, some foreign governments have accused the United States of crying wolf, reports CBS News Correspondent Joie Chen.
Mexican officials, for example, questioned why they were asked to cancel an AeroMexico flight to the United States last week.
"We've got to the stage in Western Europe where nobody actually takes any notice of American alerts anymore because there are so many of them," said British defense expert Paul Beaver.
All 115 U.S. airports that handle international flights and 14 major seaports are covered by the program, under which Customs officials can instantly check an immigrant or visitor's criminal background.
In response to the new U.S. regulations, Brazilian police started fingerprinting and photographing Americans arriving at Sao Paulo's airport last week.
Brazil's Foreign Ministry has requested that Brazilians be removed from the U.S. list.
"We want people coming to this country to work and study and to visit," Ridge told the CBS News Early Show. "But if you are a non-immigrant alien, if you are coming in for this purpose, we would like to identify you through a digital fingerprint and photo so we have an accurate record of who comes in and who leaves."
"At first, most of the Americans were angered at having to go through all this, but they were usually more understanding once they learned that Brazilians are subjected to the same treatment in the U.S.," Wagner Castilho, press officer for the federal police in Sao Paulo, said of those arriving at Sao Paulo-Guarulhos International Airport last Thursday.
Experts have said the US-VISIT system is a good idea.
"If I were a terrorist and wanted to attack western interests and knew I was gong to be fingerprinted entering the United States, frankly, I would go somewhere else," said Randy Larsen, a CBS News security consultant.
But others note the match-up won't work if the suspected terrorist has never been fingerprinted or photographed, reports CBS News Correspondent Joie Chen.
"It is the needle-in-the-haystack challenge. It's trying to find within this tremendous number of people, the few potential 'harmdoers,'" said Deborah Meyers of the Migration Policy Institute.
Under the system, inkless fingerprints will be taken and checked instantly against a national digital database for criminal backgrounds and any terrorist lists. The process will be repeated when the foreigners leave the country as an extra security measure and to ensure they complied with visa limitations.
Homeland Security spokesman Bill Strassberger said that once screeners become proficient, the extra security will take only 10 to 15 seconds per person. Foreign travelers also will continue to pass through regular Customs points and answer questions.
Photographs will be used to help create a database for law enforcement. The travel data is supposed to be securely stored and made available only to authorized officials on a need-to-know basis.
A similar program is to be installed at 50 land border crossings by the end of next year, Strassberger said.
Under the new program, a person whose fingerprints or photos raise questions would not be turned away automatically. The visa holder would be sent to secondary inspection for further questions and checks. Officials have said false hits on the system have been less than 0.1 percent in trial runs.
According to Ridge, a pilot US-VISIT program at the Hartsfield-Jackson airport has already led to 21 arrests, some of people who had been deported and were trying to reenter the country.
Congress provided $368 million to produce the system and put it in airports, but only provided $330 million of the $400 million President Bush requested to put the system in land borders in 2004.
The countries who are exempt from the system are: Andorra, Australia, Austria, Belgium, Brunei, Denmark, Finland, France, Germany, Iceland, Ireland, Italy, Japan, Liechtenstein, Luxembourg, Monaco, Netherlands, New Zealand, Norway, San Marino, Slovenia, Spain, Sweden, Switzerland, United Kingdom, Portugal and Singapore.