British and US officials are increasingly convinced that two cars found in London and laden with explosives were part of a foiled "terror plot involving Islamic extremists."
ABC News has learned that police have a clear closed-circuit television camera image of the driver of one vehicle left near Piccadilly Circus. They believe the man on the video is a known associate of jailed Islamist militant Dhiren Barot.
The two cars, both filled with "fuel, gas canisters and nails" and found near each other in central London "are clearly linked" to each other, said Peter Clarke of Scotland Yard's anti-terror command.
The first bomb, found in a silver-green Mercedes parked in Haymarket near Piccadilly Circus in the early morning hours Friday, was defused by police technicians. Later that day, police identified a suspicious blue Mercedes near Hyde Park and subsequently cordoned off Park Lane, a busy thoroughfare.
British police defused the Piccadilly Circus car bomb, made from 33 gallons of gasoline and capable of causing "significant loss of life." The bomb also included propane canisters and nails and was wired to be detonated by cell phone.
Watch World News with Charles Gibson at 6:30 p.m. EDT for the latest developments on the story.
The target of that car bomb may have been the Tiger Tiger nightclub just around the corner, with hundreds of people inside.
A robot was used to investigate the suspicious vehicle found on Cockspur Street near Park lane.
By rush hour Friday evening, Fleet Street had been reopened to traffic but Park Lane remained closed as investigators looked for a possible link to the suspicious vehicle there and the Piccadilly Circus car bomb.
Police called on Londoners to remain vigilant and promised to minimize disruptions to traffic as much as possible.
"I'd ask Londoners to be alert and report anything suspicious to the police," said Tarique Ghaffur, an assistant commander at Scotland Yard. "In incidents of this nature there is disruption and we're trying to minimize that, we're grateful to the public for their continued reporting and continued vigilance. We are working under tried and tested systems, many of which were brought in after 7/7."
Word of the Piccadilly Circus car bomb came in the early hours of Friday morning from an ambulance driver who was treating someone nearby and saw smoke coming from a blue Mercedes shortly after it careened into a barricade. The driver had apparently fled.
The alert brought central London to a standstill. Police cordoned off parts of Piccadilly Circus and surrounded the car.
Calling the device a "significant bomb," bomb technicians first approached the car with a robot. The smoke inside the car was so thick that the robot's camera could not record anything, sources said.
A bomb technician in a heavy kevlar suit approached the car and, sources say, was surprised to find a carefully constructed bomb. The bomb contained 33 gallons of gasoline in containers stuffed onto the car's right front seat and in its trunk. Also in the car were cylinders of propane and butane.
At great personal risk, sources say, the bomb technician then defused the bomb by hand.
According to U.S. security officials briefed on the matter a cell phone was to be used as a detonator.
The incident happened just hours after newly installed British Prime Minister Gordon Brown announced his new Cabinet. He said the British people must remain vigilant