A much-disrupted British Airways flight from London to Washington, D.C. has been canceled again over security fears, the airline said yesterday in the British capital.

　　Britain's national carrier said flight 223 from Heathrow to Washington's Dulles Airport would not fly on Sunday.

　　Monday's flight 263 from London to Riyadh, Saudi Arabia, also was scrapped.

　　The airline, one of Europe's big-four carriers, said the decision "follows government advice to cancel those flights for security reasons."

　　The 184 people booked on the Washington flight and 149 Riyadh passengers would be rebooked on other flights or given a refund, the airline said.

　　Ba said the return flights to London would operate as scheduled.

　　Flight 223 has been delayed or canceled eight previous times this year because of heightened US security alerts that came into effect after the September 11, 2001, terrorist attacks on the country.

　　Saudi flights also have been canceled several times.

　　Officials in Britain have refused to say what intelligence prompted them to advise cancellation of the BA flights, but authorities in the United States have spoken of a "specific and credible" terrorist threat toward international flights.

　　Disruption to flight 223 began on December 31, when the plane was kept on the tarmac at Dulles for several hours after landing, while authorities in the United States questioned passengers and crew.

　　Ba scratched the same service the following two days and several times after that, most recently on February 2. When the flight has gone ahead, it has sometimes been delayed for hours for stringent checks on passengers.

　　The carrier's two other daily flights to Washington have not been affected.

　　Last august, BA suspended service to Saudi Arabia, where the British government warns of "a continuing threat of terrorism," after local authorities broke up a cell that reportedly was plotting an attack on a British plane.

　　Service was restored in September.

　　Several paris-based Air France flights to the United States and a Continental Airlines Glasgow-to-Los Angeles flight also have been canceled in the past few weeks.

　　Air france said yesterday in Paris that its flights were running normally and there had been no cancellations for security reasons.

　　Some european officials have questioned the need for the flight disruptions, and Britain's pilots' union has expressed concern over the "erratic" nature of the intelligence leading to the cancellations.

　　A request by the United States for armed "sky marshals" to travel on flights thought to be at risk also has caused friction.

　　Britain's air Line Pilots' Association has expressed strong opposition to the idea.

　　British airways said the air marshals might be acceptable in some circumstances.