British authorities say they have disrupted a terrorist plan to blow up airliners flying between Britain and the United States.
A senior police official in London (Deputy Commissioner Paul Stephenson) says the plot was "intended to be mass murder on an unimaginable scale."
Intelligence officials in Britain and the United States say terrorists planned to smuggle liquid explosives onto as many as 10 American airliners (from United, American and Continental airlines) and destroy the aircraft during trans-Atlantic flights. Security has been tightened at airports in Europe and the United States, with many flights cancelled and severe restrictions on what passengers are allowed to bring aboard.
Police in Britain have arrested 21 people and are searching for other suspects in London and other communities. No details about the suspects have been made public, but a top British anti-terrorist officer (Peter Clarke) said the plot had "global dimensions."
Britain and the United States both raised security threat levels for air travel. Passengers are now forbidden to bring liquids aboard planes, including beverages and cosmetics -- indicating that the terror plot centered on a plan to use liquid explosives.
British government officials say Prime Minister Tony Blair briefed President George Bush about the situation as the predawn police raids were taking place in London.