Washington ? Six U.S.-bound flights from England, Scotland and France were canceled Saturday after U.S. authorities warned French and British counterparts about intelligence reports indicating that al-Qaida terrorists might target the flights.

British Airways grounded the same flight scheduled today and Monday from London’s Heathrow Airport to Dulles International Airport outside Washington, as well as the return flights. Also canceled was a flight from London to Miami today. Continental Airlines said it canceled Flight 17 for today from Glasgow, Scotland, to Los Angeles with an intermediate stop in Newark, N.J.

Air France scrubbed the same flight set for today and Monday from Charles de Gaulle Airport in Paris to Dulles. As a result, the outbound flights were canceled.

“We continue to receive threat reporting that indicates al Qaida’s desire to target international aviation,” said Brian Roehrkasse, spokesman for the Homeland Security Department.

Despite those threats, Roehrkasse said the department had no plans to raise the nation’s terror alert level from yellow, or elevated risk of terrorist attack. Yellow is in the middle of the five-color coded scale.

The decision to cancel the flights was made jointly by the U.S., British and French governments, according to a senior U.S. law enforcement official speaking on condition of anonymity.

The U.S. government official said the threat information picked up by intelligence agencies specifically mentioned British Airways flight 223 from London to Dulles; British Airways flight 207 from London to Miami; and Air France flight 026 from Paris to Washington.

The official said the three countries discussed a variety of aviation security steps, such as sky marshals on the U.S.-bound flights, but that Washington placed no demands on the French or British.

The official said there was no direct intelligence to indicate any threat to today’s Super Bowl game in Houston.

A White House spokesman, Trent Duffy, said the cancellations showed that “the administration is going to stand guard and protect the American people.”

The law enforcement official said that for weeks, intelligence sources had picked up indications of al-Qaida’s continued interest in using airlines as weapons. But the official said that in the past week the intelligence became more specific, singling out certain flights and airlines.

British Airways Flight 223 did take off Saturday from London and arrived as scheduled Saturday evening in Washington, as did Air France 026.

As Dennis Lopez, a lawyer from Tampa, Fla., boarded the British Airways flight, he said the talk of all the cancellations was unnerving.

“I’m a little worried, and if I had another flight arrangement right now that could take me there, I would definitely take advantage of that,” he said.

He said he had just arrived from Kuwait and “breathed a sigh of relief” when he landed in London, thinking he was out of the area of most concern. “It hadn’t occurred to me that this flight could be a possible target,” he said.

In Miami, people arriving on BA Flight 207 from London said they did not know about the security concerns that led to that flight’s cancellation today.

“They certainly didn’t announce that on the flight,” said Rob Willows, of Colchester, England.

Added flight attendant Steven Southern: “We were aware that there was security threats with all the East Coast flights, but that’s all we knew.”

Likewise, at least a half-dozen of the first passengers off BA Flight 223 at Dulles on Saturday evening said they had been unaware of any security concerns.

Another passenger, Anurag Varma of Arlington, Va., said he did not know anything about security concerns when he got to Heathrow, but learned via the Internet about the flight cancellations for next two days and then became concerned.

“I was petrified,” he said. “I kept thinking I should get off the flight.” But he said he decided to stay on the flight after a BA official told him she was unaware of any security concerns.

“This is the most nervous I’ve ever been to fly,” he said.

Varma said he noticed in London that each passenger was carefully screened about questioned by security personnel, but that he was told such actions were routine. He said he was asked the purpose of his visit to London, where he stayed there and who he had been with.

Some of the flights that have raised concerns are the same as those that drew increased attention when the U.S. terror alert was raised temporarily to orange, or high risk, before Christmas.

It returned on Jan. 9 to yellow, though government officials said heightened security would remain at some airports and in some cities, such as New York, Washington and Los Angeles.