LONDON — Terrorists ripped into the heart of the British capital in a series of apparently coordinated explosions during yesterday’s morning rush hour, killing at least 37 and injuring hundreds while bringing chaos to the city’s subways, bus systems and car-jammed streets.
London was already on the second-highest security alert because of the Group of Eight summit in Gleneagles, Scotland, but there was no warning of the carnage that began as about 3 million commuters streamed through summer wind and rain to their jobs in the British capital.
The first blast — a bomb purportedly triggered by a shadowy offshoot of Osama bin Laden’s al Qaeda terrorist organization — tore through a train 100 yards from Liverpool Street station in the city’s eastern sector at 8:51 a.m., killing at least seven persons.
Within the next 56 minutes, explosions also struck the underground rail stations at King’s Cross/Russell Square and Edgware Road, and a bomb blew the top off one of London’s famed double-decker buses, which was loaded with commuters who had just fled one of the subway attacks.
Shocked survivors found themselves escaping through scraps of confetti from the previous night’s celebration of London’s being awarded the 2012 Olympic Games.
By evening, Scotland Yard had put the official death toll at 37, and the number of injured was reported at more than 700 commuters and tourists. Authorities said both figures were destined to rise as rescue crews dug into the wreckage at the rail stations and the demolished bus.
Police were investigating whether suicide bombers were involved, but a senior U.S. intelligence official said in a briefing last night there was no evidence yet of suicide bombers or a remote-controlled device being used. He added that there was evidence of timing devices being used.
“I do have information that timing devices appear to have been used in some of the attacks,” he said.
A U.S. law-enforcement officer said British authorities had told him that at least 40 persons had died, and French Interior Minister Nicolas Sarkozy told the Reuters news agency that he had been advised by British Home Secretary Charles Clarke that the death toll was at least 50. Two young women from Knoxville, Tenn., were among those treated for injuries, said their father, Dudley Benton.
The highest death toll was 21 persons at the King’s Cross subway station, according to Scotland Yard. Seven were confirmed killed at Liverpool Street station, seven at Edgware Road station — the heart of a thriving Muslim community — and two on the bus.
It was the deadliest attack on London since World War II, far exceeding the tolls from a series of Irish Republican Army attacks spanning three decades until 2000.
ABC News last night quoted U.S. authorities as saying officials had discovered two more unexploded bombs and recovered timing devices from some of those that went off, potentially providing clues to the identity of the attackers.
The home secretary, who described the attacks as “mass murder,” said he would “find it difficult to believe” that the attacks were not linked to the opening of yesterday’s G-8 session in Scotland. It was attended by leaders of the world’s most-industrialized nations, including President Bush.
In Gleneagles, a visibly shaken Prime Minister Tony Blair, surrounded by leaders of the G-8 nations, appeared on television shortly after the blasts to tell the nation “it’s reasonably clear that there have been a series of terrorist attacks” in central London.
Mr. Bush told Americans that they must be “extra vigilant.” His administration ratcheted up the terror alert for mass transit to Code Orange, the second-highest level.
Mr. Blair, who immediately flew to London to consult with security officials, called it “a very sad day for the British people” and described the attacks as “barbaric.”
The descriptions provided by witnesses underscored that comment. One said the double-decker bus was “ripped open like a can of sardines.”
“I was on the bus in front and heard an incredible bang,” said Belinda Seabrook of London. “I turned round and half the double-decker bus was in the air. It was a massive explosion, and there were papers and half a bus flying through the air.”
Public-relations worker Simon Corvett of Oxford was aboard a train leaving the Edgware Road station when “all of a sudden there was this massive, huge bang. It was absolutely deafening, and all the windows shattered.”
“There were just loads of people screaming, and the carriages filled with smoke,” Mr. Corvett said. “You couldn’t really breathe, and you couldn’t see what was happening.”
What he did see was horrifying.
“You could see the carriage opposite was completely gutted,” he said. “There were some people in real trouble.”
At the Liverpool Street explosion site, student Sarah Reid said she saw the force of the blast rip one rail car apart, blowing off its roof.
“The carriage was split in two, all jagged, and without a roof, just open. I saw bodies, I think.”
The multipronged attack stunned London and the nation, but it did not catch them by total surprise. Since the September 11, 2001, terrorist attacks on New York and the Pentagon, the British capital has been on alert to a greater or lesser degree, while systems for dealing with such an attack were developed and put into place.
Yesterday, the well-rehearsed emergency plans worked. Within minutes after the first blast, London’s entire subway network was shut down, and most of it remained that way the rest of the day while police, firefighters, doctors and nurses swung into action.
With police help, ambulances wove their way through chaotic traffic jams — and when there weren’t enough ambulances, double-decker buses, seven at one point, were commandeered to haul the victims to hospitals.
When hospitals ran short of space, nearby hotels, such as the Hilton London Metropole near Edgware Road, were turned into makeshift emergency rooms.
Mr. Clarke went on radio and television to tell Londoners that “underground services have been suspended, and we advise people not to make unnecessary journeys in London at this stage in order to help the police and other emergency services deal with the current situation.”
As sunset neared, much of the below-surface subway remained closed, but surface sections of the transit system were slowly coming back into operation. All the city’s commuter train stations were back in operation and telling travelers that trains were ready to get them to their suburban and country homes.
Investigators quickly got busy, and among their immediate targets were the thousands of closed-circuit television cameras that make London’s population one of the most photographed in the world. What police hoped for were pictures of the terrorists.
In Washington, Attorney General Alberto R. Gonzales said the Justice Department, including the FBI, “has informed the British authorities that we stand ready to assist them in any way possible.”
A little-known splinter group calling itself the “Secret Organization Group of al Qaeda Jihad Organization in Europe” took responsibility for the attacks, and Foreign Secretary Jack Straw said the bombings bore all the hallmarks of an al Qaeda operation — similar in many respects to the March 2004 attacks on Madrid’s railway network, which killed nearly 200 people.
The message, posted on an Internet Web site yesterday morning, said: “The heroic mujahedeen carried out a blessed raid in London. Now, Britain is burning with fear, terror and panic in its northern, southern, eastern and western quarters.”
British police said they were unable to verify the claim, nor could they determine immediately whether suicide bombers had been used to carry out the attacks.
London’s Metropolitan Police Commissioner Ian Blair said that authorities had received no warning of the attacks, but that “a coordinated effort is slowly bringing order out of the chaos.”
“Within a matter of hours,” he said, “peace will be brought to the streets of London, and we will know exactly what we are dealing with.”
At the same time, a police spokesman warned, “We must be vigilant. We don’t know if this is over.”
The British flag was lowered to half-staff over Buckingham Palace at the instructions of a “deeply shocked” Queen Elizabeth II. Mr. Blair’s ministers announced that the standard would be similarly flown over government buildings today.
Jerry Seper of The Times and Shaun Waterman of United Press International contributed to this article, which was based in part on wire service reports.