(AP) - The U.S. government issued its highest terrorism alert ever for commercial flights from Britain to the United States early Thursday after a terror plot was disrupted in London, with a specific concern for tourist-filled flights to major U.S. cities.
Terrorists had targeted United, American and Continental airlines, two U.S. counterterrorism officials said, reports Trend.
"The plot was to board international flights, potentially headed to the U.S., with bombs fashioned in a way that they would be in carry-ons, and blow them up in midair," one intelligence official said. This official said the terrorists had hoped to target flights to major airports in New York, Washington and California, all major summer tourist destinations.
In addition to the highest alert for flights from Britain, the alert for all flights coming or going from the United States was also raised slightly, to orange. The government banned beverages, hair gels and lotions from flights, explaining only that liquids emerged as a risk from the investigation in Britain.
It is the first time the red alert level in the Homeland Security warning system has been invoked, although there have been brief periods in the past when the orange level was applied. Homeland Security defines the red alert as designating a "severe risk of terrorist attacks."
One intelligence official said the first-ever red alert signaled extreme concern within the government. "We are concerned enough to put the highest wall up we can," this official said.
Officials said the government has been aware of the nature of the threat for several days, and President Bush was fully briefed.
Homeland Security Secretary Michael Chertoff issued a statement overnight.
"We believe that these arrests (in London) have significantly disrupted the threat, but we cannot be sure that the threat has been entirely eliminated or the plot completely thwarted," Chertoff said in announcing that the threat level for flights from Britain to the United States has been raised to the highest "severe or red" level.
"To defend further against any remaining threat from this plot, we will also raise the threat level to high, or orange, for all commercial aviation operating in or destined for the United States," Chertoff said.
A statement issued by Chertoff said "currently, there is no indication ... of plotting within the United States."
A U.S. law enforcement official said there have been no arrests in the United States connected to the plot.
A senior U.S. counterterrorism official said authorities believe dozens of people were involved or connected to the overseas plot that was unraveled Wednesday evening. The plan "had a footprint to al-Qaida back to it," said the official, speaking on condition of anonymity because of the sensitivity of the situation.
It was not believed to be connected to the Egyptian students who disappeared in the United States more than a week ago before reaching a college they were supposed to attend in Montana. Three of the 11 have since been found and the FBI has said neither they nor the still-missing eight are believed to be a threat.
The plan involved airline passengers hiding masked explosives in carry-on luggage, the official said. "They were not yet sitting on an airplane," but were very close to traveling, the official said, calling the plot "the real deal."
U.S. intelligence has been working closely with the British on the investigation, which has been ongoing for months, the second official said.
Authorities have not yet arrested or detained all suspects who are believed to be involved in the plot, the official said, prompting Chertoff's alarm.
"Consistent with these higher threat levels, the Transportation Security Administration is coordinating with federal partners, airport authorities and commercial airlines on expanding the intensity of existing security requirements," Chertoff 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."
He said the changes take effect at 4 a.m. local time across the United States and will be undated as warranted.
The metal detector and X-ray machines at airport security checkpoints cannot detect explosives. At many, but not all airport checkpoints, the TSA has deployed walkthrough "sniffer" or "puffer" machines that can detect explosives residue.
As part of the foiled Bojinka Plot to blow up 12 Western airliners simultaneously over the Pacific Ocean in the mid-1990s, terrorist mastermind Ramzi Youssef planned to put together an improvised bomb using liquid in a contact lens solution container.
Chertoff said travelers in the United States "should also anticipate additional security measures within the airport and at screening checkpoints."
"These measures will continue to assure that our aviation system remains safe and secure," Chertoff added. "Travelers should go about their plans confidently, while maintaining vigilance in their surroundings and exercising patience with screening and security officials."
At U.S. Northern Command, the military headquarters established in response to the Sept. 11, 2001, attacks to improve coordination of the defense of U.S. territory, spokesman Sean Kelly declined to comment on any precautionary steps taken in response to the heightened threat levels.
"It is inappropriate to speculate or comment on any current operational activities or discuss future force protection measures," he said.
Prime Minister Tony Blair's office said in London that the prime minister, vacationing in the Caribbean, had briefed Bush on the situation overnight.
The Homeland Security Department devised the alert system after the Sept. 11 attacks. The last time the U.S. government raised the terrorist risk here to orange, or high, was in July 2005 after the subway bombings in London. It was lowered to yellow a month later, the elevated risk status that has been the norm since the system was created.
In London, Britain's Home Secretary John Reid said the alleged plot was "significant" and that terrorists aimed to "bring down a number of aircraft through mid-flight explosions, causing a considerable loss of life."
Police arrested a number of people overnight in London after a major covert counterterrorism operation that had lasted several months, but did not immediately say how many. Heathrow airport in London was closed for most European flights.