Police thwarted a car bomb attack Friday in London's bustling nightclub and theater district, defusing a crude explosive device made of gasoline, propane gas and nails after an ambulance crew spotted smoke coming from a green Mercedes outside a nightclub. Hours later, police confirmed that a second car bomb was found in the center of the city.
The first car bomb, found near Piccadilly Circus, was powerful enough to have caused "significant injury or loss of life" at a time when hundreds were in the area, British anti-terror police chief Peter Clarke said.
Clarke said Friday evening that the second car — a blue Mercedes — was originally parked illegally on nearby Cockspur Street, but had been towed from the West End to an impound lot near Hyde Park.
"The vehicle was found to contain very similar materials to those that had been found in the first car," he said. "There was a considerable amount of fuel and gas canisters. As in the first vehicle, there was also a quantity of nails. This like the first device was potentially viable."
A British government official told FOX News that Scotland Yard investigators believed the bomb found near Piccadilly Circus was to be triggered remotely.
Britain's Sky News also quoted a police source as saying the device was to be set off remotely by cell phone. A police officer risked his life by removing the remote trigger from the vehicle before the device could be set off, the source was quoted as saying.
Fleet Street, once the center for British journalism, was also closed briefly while police inspected a suspicious vehicle. The cordon was taken down and traffic allowed into the area as soon as police dismissed the threat.
Britain's new home secretary, Jacqui Smith called an emergency meeting of top officials, calling the attempted attack "international terrorism."
"We are currently facing the most serious and sustained threat to our security from international terrorism," she said afterward. "This reinforces the need for the public to remain vigilant to the threat we face at all times."
The events began when an ambulance crew — responding to a call just before 1:30 a.m. about a person who had fallen at a Haymarket nightclub — noticed smoke coming from a car parked in front of the building, Clarke said.
The crew alerted police, and a bomb squad manually disabled the device, Clarke said.
Photographs of the metallic green Mercedes show a canister bearing the words "patio gas," indicating it was propane, next to the car. The back door was open with blankets spilling out. The car was removed from the scene after a bomb squad disabled the explosives.
The busy Haymarket thoroughfare inthe theater district is packed with restaurants, bars, a cinema complex and West End theaters, and was buzzing at that hour. "Phantom of the Opera" is playing at Her Majesty's Theater down the street.
It was ladies' night Thursday, nicknamed "Sugar 'N' Spice," at the Tiger Tiger nightclub, a three-story venue that at full capacity can pack in 1,770 people and stays open until 3 a.m.
Police also were investigating the possibility that the planned attack could have been criminal in nature. Authorities closed the Piccadilly Circus subway station for eight hours and cordoned off a 10-block area around the scene.
A British security official, who spoke on condition of anonymity because of the sensitivity of the security details, said there were similarities between the device and vehicle bombs used by insurgents in Iraq. But the two officials in Washington said it was too early in the investigation to tell if those similarities were significant.
The British security official also said the domestic spy agency MI5 would examine possible connections between Friday's bomb attempt and at least two similar foiled plots — to attack a London nightclub in 2004 and to pack limousines in New York with gas canisters and shrapnel.
In the 2004 plot, accused members of an Al Qaeda-linked terror cell were convicted of conspiring to cause explosions. One of the possible targets M15 overheard them discussing was the Ministry of Sound, one of London's biggest and most famous nightclubs.
One man is heard saying the plan was to "Blow the whole thing up."
Gordon Brown, who only Wednesday succeeded Tony Blair as prime minister, called it a reminder that Britain faces a serious and continuous threat of terrorist attacks: "I will stress to the Cabinet that the vigilance must be maintained over the next few days."
There had been no prior intelligence of planned attacks from the Al Qaeda terror network, a British government official told The Associated Press on condition of anonymity because of the sensitivity of the investigation.
Londoners were relatively unfazed by the news. People crowded onto buses and subway trains during the afternoon rush hour, shopping streets were busy and sidewalk cafes did brisk business.
"Sure, it's disturbing, and obviously it reminds everyone of 7/7," said Ian Hiskos, 32, eating at a cafe across the block from the police cordon on Haymarket. "I try not to think about these things."
The terror threat level in Britain has remained at "severe" — meaning a terrorist attack is highly likely — since last August.
On Friday, Metropolitan Police said it sent more officers on the streets of central London. Authorities also stepped up security at Wimbledon.
One analyst said the bombers could be trying to send Britain's new leader a message.
"It's a way of testing Gordon Brown," said Bob Ayers, a security expert at the Chatham House think tank. "It's not too far-fetched to assume it was designed to expedite the decision on withdrawal (from Iraq)."
U.S. Homeland Security officials said the event had been classified as a "local incident" and there would be no change to the threat level in the United States.
President Bush, who is at his family's home in Kennebunkport, Maine, was briefed by National Security Adviser Stephen Hadley about the apparent terror attack.
"We commend the British security services and local officials for their action today," National Sercurity Council spokesman Gordon Johndroe said. "U.S. officials are in contact with their U.K. counterparts and will continue to monitor the situation."
New York strengthened its already tight security as a precaution, putting additional police in Times Square and the mass transit system.
"We're going to ramp up a little bit, but nothing dramatic," Mayor Michael Bloomberg said on his weekly radio show. "We'll take a little bit of extra precaution. Some of you will notice, some of you won't — but we have to be cognizant."
The Associated Press contributed to this report.