WASHINGTON — U.S. authorities tonight say London terrorists were within just a few days of a test flight to see if they could get their bomb components onto a plane. If the answer was yes, they were prepared to actually stage the attacks.
U.S. officials say this was a carefully thought-out and well-financed operation, with all the earmarks of al-Qaida.
The apparent plan: Two-man teams would bring chemicals through security that are harmless on their own, then assemble them on board, forming powerful explosives for suicide attacks.
"The terrorists planned to carry the components of the bombs, including liquid explosive ingredients and detonating devices disguised as beverages, electronic devices, or other common objects," said Homeland Security Secretary Michael Chertoff at a news conference Thursday.
Among the components: common household liquids, easily available at drug and hardware stores, which could be carried in drink containers. While an intelligence bulletin says the explosives were to be peroxide-based, NBC News is not disclosing the specific chemicals or possible detonators.
Investigators say the plotters had not decided on specific flights to attack, but within the past few days were clicking around the Internet, looking at non-stop flights from the U.K. to the U.S. that left around the same time.
"They had focused on a number of airlines involved which have specific routes between Britain and the United States and which are U.S. flag carriers," said Chertoff.
U.S. officials say British investigators had the terror cell under close surveillance for several months, keeping the U.S. informed, then adding more specifics just within the past several days, when the plotters focused on planes headed here.
For the past several days, the FBI has feverishly looked for any potential ties to people in the U.S., but has so far found none.
"We literally in the last couple of weeks have had hundreds of FBI agents around the country tracking down every lead, and we have not found to date any plotters here in the United States," said FBI Director Robert Mueller.
Aviation experts say airport screening devices have a hard time picking up the chemicals the plotters planned to use, something officials verified with a test Thursday morning at Washington's Ronald Reagan National Airport.
As for the terror threat system, there's no idea how long it will remain at its higher levels. Was this to be the spectacular attack many worried might happen?
There's no doubt that, if successful, this could have been as devastating as 9/11 itself. U.S. officials say they believe all the U.K. terror plotters have been identified or arrested. But they're raising the treat level up for two reasons: They cannot be certain everyone's been found and they want to guard against possible copycat attacks.