A bus was ripped apart in an explosion in central London today and several blasts rocked the Tube network leaving dozens of people injured.
The Tube blasts at the height of the rush hour on Thursday were initially blamed on a power surge.
But amid the chaos eyewitnesses reported that a packed double decker bus in the Russell Square area had been severely damaged in a blast.
Union officials blamed the Tube blasts on a series of bombs, and Scotland Yard confirmed the bus explosion and said it was dealing with "multiple explosions" in London.
Tony Blair acknowledged that the attacks were terror-related:
Two people have been killed and scores have been injured after at least seven blasts on the Underground network and a double-decker bus in London.
UK Prime Minister Tony Blair said it was "reasonably clear" there had been a series of terrorist attacks.
He said it was "particularly barbaric" that the attack was timed to coincide with the G8 summit which he would be leaving to return to London.
London's police chief said traces of explosive had been found at one site.
Sir Ian Blair urged people to stay where they were and not to call emergency services unless it was a life-threatening situation.
One caller to BBC Five said his friend had seen "the bus ripped open like a can of sardines and bodies everywhere".
Loyita Worley, who works for a City law firm, said she was on the underground train when an explosion took place in the next carriage, while it was in a tunnel.
The 49-year-old said: "All the lights went out and the train came to an immediate halt. There was smoke everywhere and everyone was coughing and choking, but remained calm. We couldn't open the doors."