British officials say police are confident they have captured all the main figures in an alleged plot to blow up U.S. airliners over the Atlantic Ocean.
Home Secretary John Reid spoke Thursday after police arrested 24 people in London, Birmingham and southeastern England following an eight-month surveillance operation.
U.S. and British news reports say five suspects are still at large.
British and U.S. officials say a martyrdom video was found during Thursday's raids, and that the suspects could have been just days away from carrying out their plan.
The officials say the suspects were ready to smuggle liquid explosives onto as many as 10 U.S. airplanes including United, American and Continental airliners.
If the alleged plot had been carried out, Reid says there would have been an unprecedented loss of innocent civilian lives.
Top British and U.S. officials say the plot is similar to a failed 1995 al-Qaida plot to blow up a number of airliners over the Pacific.
British Prime Minister Tony Blair Thursday thanked British police and intelligence agents for their "immense effort" in protecting the country.
Al-Qaida terrorists hijacked four aircraft in the United States on September 11, 2001, flying them into the World Trade Center in New York and the Pentagon. A fourth airliner crashed on its way to another major Washington target.
In December 2001, Briton Richard Reid was arrested trying to set off a bomb hidden in his shoe on a commercial passenger jet.
Some information for this report provided by AP, Reuters.