Series Of Explosions In London

London has been targeted by a wave of at least four separate terrorist attacks that have paralyzed the city's transport network and caused at least 37 fatalities and 700 casualties.

In what looks like a major co-ordinated attack on London, several explosions tore through the city's underground rail network during the morning rush hour and another bomb ripped the roof off a double-decker bus packed with commuters.

The blasts come only one day into the G-8 summit, where the leaders of the world's richest nations are gathered in Scotland. Prime Minister Tony Blair held two press conferences before leaving Gleneagles to return to his official residence at 10 Downing Street in London.

	A Second Wave of Bombings • London Attacked Again A new round of blasts shake London • Photos: London's mass transit system suffers four new blasts • Map: The July 21 attacks The First Attacks • Back to Work TIME's staffers give first-person accounts of their morning journey as Londoners return to their commute the day after a deadly attack • The Rail System • A Cyclist's Haven • On the Buses • Walking the Walk • Photos: Eyewitness Images of the Attacks Personal cameras and cell phones record the terror of the day • Series of Explosions in London Dozens die as terrorists hit Britain's capital in the crowded rush hour • President Bush Responds to London Attacks In Gleneagles, the President says he'll continue the fight on terror • Photos: London Carnage • Map: The Bombings • Question of the Week • TIME Collection: al-Qaeda • Photos: A New Blitz Fortune.com • The July 7 London Blasts: A Firsthand Account A FORTUNE editor finds himself on a bus right behind the one that was bombed today in the U.K. CNN.com • Special: London Terror • Complete Video Coverage

At the second conference the entire assembly of G-8 leaders, plus Kofi Annan and a host of other world leaders stood behind Blair in a show of solidarity. This time, though still visibly disturbed, he spoke with force and resolve.

"Today's bombings will not weaken in any way our resolve to uphold the most deeply held principles of our societies and to defeat those who would impose their fanaticism and extremism on all of us. We shall prevail. They shall not." Blair plans to rejoin the other world leaders this evening.

Coming the morning after London won the 2012 Olympic bid, the mood in the U.K. capital has changed from widespread jubilation to shock and confusion. Hundreds of police and scores of ambulances packed the city center as medics tried to treat the victims of the attacks at the various locations.

Only 100 yards from the British Museum, London's Russell Square in Bloomsbury, considered the heart of literary London, is usually a calm and leafy oasis sheltering cafes full of the chattering classes. But today swarming, panic-stricken crowds packed the square, as police screamed at people to clear the area after two unexpected explosions brought the neighborhood to a screeching halt.

Signs of the first explosion, at 0856 on the Piccadilly tube line between Kings Cross and Russell Square underground stations, were not immediately visible. But the target of the second bomb was all too clear. Only one block away, strewn on its side in the road, an iconic red London double-decker bus lay destroyed, its roof ripped off like an open sardine can.

Peter Gordon, 30, heard the blast from inside the British Medical Association building, opposite the bomb site, which blew out all the windows on the ground floor of the building. Dense smoke meant it was difficult to see what was going on but people were clearly strewn on the ground. Others on the other side of the road saw people screaming and running away from the bus obviously wounded. The front of the BMA building was covered with blood.

One man interviewed by TIME received a panicked call from his partner saying "I'm alive," before he even knew of the explosions. She says she was on a Piccadilly line tube train when the carriage appeared to derail in a tunnel somewhere between Kings Cross and Russell Square. Her carriage, near the drivers compartment, was tossed on its side, leaving shattered glass flying through the carriage and bodies thrown onto the tracks. "She said lots of people who were still OK were stopping to help as they tried to find they way out of the tunnel. Then she just kept asking me if anyone had been killed." But with mobile phone networks unable to cope with the increased activity he was unable to find out where she had been.