US authorities have adopted tougher passenger checks on flights from France and Britain in the past week, and this has contributed to the cancellations, a Department of Homeland Security (DHS) spokesman said.

Seven flights heading for the United States - three from France, two from Britain and two from Mexico - have been cancelled due to security fears since the US government heightened its nationwide terror alert from "elevated" to "high" on 21 December.

British Airways on Friday cancelled a London-Riyadh flight, scheduled to leave on Saturday, for security reasons.

The US under secretary for border and transportation security, Asa Hutchinson, said the cancellations were justified but it may never be known if a terrorist attack had been stopped.

"We made the right decisions," he told CNN television, adding the decisions to halt the flights were "based on specific intelligence concerns that we have."

Cancelled flights

Three Paris-to-Los Angeles Air France flights were cancelled on 24 and 25 December. US intelligence had highlighted potential terrorists on the halted flights, but French and US officials now admit that none of the names belonged to terrorist suspects.

British Airways stopped flights to
Washington Thursday and Friday

F-16 fighter jets escorted at least two Air France planes bound for Los Angeles on Tuesday and Wednesday, The Washington Post reported.

Separately, the DHS said on Friday a British Airways flight to Washington had been the last flight to receive a "Combat Air Patrol F-16 escort".

A British Airways flight to Washington was cancelled Friday for the second day in a row. British Airways said BA Flight 223 from London to Washington had been cancelled for a second straight day for "security reasons".

Meanwhile, an Air France flight from New York to Paris was rerouted overnight to Newfoundland in Canada for security reasons, the company said on Friday.

"The pilot preferred to land in Newfoundland to unload a piece of luggage put on the plane in error," the airline said.

Checking passengers

The DHS spokesman said both French and British authorities were also now providing passenger lists shortly before take off.

"It's the protocol we hope will be used as a template with other countries, to be able to do this on other countries' airlines," the spokesman said.

Asked if passenger lists for every foreign flight to the United States were being provided just before departure, the spokesman replied: "Where we have intelligence pertinent to specific airlines, specific flights or flight numbers, we're working that angle."

He said that in some instances background checks were also being sought on flight crew members.

US officials have recently announced foreign airliners entering US airspace could be required to have armed marshalls on board.

Some 122 million people flew in and out of the United States during the 2002 fiscal year, which ended 30 September, according to the latest Immigration and Naturalization Service and Commerce Department records.