LONDON, England (CNN) — British police say they have arrested 21 people in connection with a terrorist plot to blow up aircraft flying from the United Kingdom to the United States.
The plot was «intended to be mass murder on an unimaginable scale,» Metropolitan Police Deputy Commissioner Paul Stephenson said. The UK’s threat warning level has been raised to «critical» — meaning «an attack is expected imminently.»
London Heathrow — one of the world’s busiest airports — was closed to most European flights Thursday morning, causing chaos for thousands of travelers. British Airways canceled all its flights between the airport and points in Britain, Europe and Libya. (Full story)
The plot involved hiding liquid explosives in carry-on luggage, and six to 10 flights would have been targeted, U.S. officials said.
Some flights would have been heading from the UK to New York, Washington D.C. and California, the officials said.
The plot involved Continental, United, and American Airlines, according to an administration official who noted that the list was not exclusive.
The intelligence that uncovered the plot «makes very strong links to al Qaeda,» a senior U.S. administration official told CNN. The official said it is believed the plot was close to being operational.
U.S. President George W. Bush and British Prime Minister Tony Blair had conversations concerning the terror plot investigation over the weekend and the leaders have spoken several times since, including overnight when the arrests were made, the official said.
British and U.S. security agencies moved to limit carry-on items on Thursday, causing extended delays at airport security checkpoints. The British Airports Authority said no hand luggage would be allowed onto planes leaving UK airports. (Full story)
Stephenson said 21 people had been arrested by London, Birmingham and Thames Valley police overnight in an ongoing operation.
«This is about people who are desperate … who want to do things that no right-minded citizen of this country or any other country would want to tolerate,» Stephenson said.
The arrests were the result of a «covert counter-terrorist operation,» police said. «It is believed that the aim was to detonate explosive devices smuggled on board the aircraft in hand luggage.»
U.S. Homeland Security Secretary Michael Chertoff said it was unclear if British authorities had arrested everyone involved in the plot.
But Britain’s Home Secretary John Reid said police were confident the main players involved in the plot had been accounted for, adding the operation was ongoing and further arrests might be made.
Asked if Britain’s Muslim community was involved in the investigation, Reid would not comment. «We are involved in a long wide and deep struggle against very evil people,» Reid said. «This is not a case of one civilization against another, one religion against another.»
The Metropolitan Police confirmed they have evacuated an undisclosed number of houses in High Wycombe, north of London, in connection with the raids.
Deputy Assistant Commissioner Peter Clarke, Head of the Metropolitan Police Service Anti-Terrorist Branch, said the arrests followed an «unprecedented level of surveillance» over several months involving meetings, movements, travel, spending and the aspirations of a large group of people.
In the United States, the Department of Homeland Security raised the terror threat to the highest level of «severe,» or red, for commercial flights originating in the United Kingdom bound for the United States.
In addition, the threat level has been raised to «high,» or orange for all commercial flights operating in or coming to the United States, a DHS statement said.
«Due to the nature of the threat revealed by this investigation, we are prohibiting any liquids, including beverages, hair gels, and lotions from being carried on the airplane,» the statement said.
In a statement, Blair said: «I would like to pay tribute to the imense effort made by the police and security services who for a long period of time have tracked this situation and been involved in an extraordinary amount of hard work. I thank them for the great job they are doing in protecting our country.
«There have been an enourmous amount of co-operation with the U.S. authorities which has been of great value and underlines the threat we face and our determination to counter it.»
A U.S. Transporation Safety Adminstration official said travelers should show up at least two hours ahead of their flights and bring plenty of patience. According to the DHS, there is no indication the plot involved American counterparts.
The July 7, 2005, train and bus bombings that killed 52 London commuters and four bombers was an attack staged by British-raised extremists.
The alleged terror plot comes nearly five years after Briton Richard Reid attempted to detonate explosives hidden in his sneakers on an American Airlines flight from Paris to Miami in December 2001.
Passengers thwarted his plan, and the plane landed safely in Boston. Reid pleaded guilty to terrorism charges in October 2002 and is serving a life sentence at the nation’s super-maximum security prison in Florence, Colorado.
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