London has been hit by a series of explosions across the London underground tube system and at least one double-decker bus has been targeted as well. The explosions happened during Thursday morning rush hour, and initial reports are that terrible injuries have been caused. Officials have closed down the entire underground system.

The near simultaneous explosions came just a day after London celebrated being awarded the 2012 Olympics, and as the G8 Summit commenced in Scotland.

Previous reports blamed a power surge, but with the explosions on the bus and the denial by the power companies, it seems that an intentional attack has taken place on England’s capital.

Home Secretary Charles Clarke said, "There have been a number of dreadful incidents across London today," and he said that there had been some terrible injuries.

One witness named Darren Hall described passengers emerging from the evacuated subway station with soot and covered in blood.

Metropolitan Police Commissioner Sir Ian Blair said there had been at least six explosions, but said the picture was still "very confused".

Scotland Yard have reported that explosions have been confirmed at Edgware Road, King's Cross, Liverpool Street, Russell Square, Aldgate East and Moorgate.

Sky News have released picture of a mangled red bus; police said they suspected a bomb caused the explosion. Police confirmed that it was an explosion that destroyed a double-decker bus at Russell Square in central London.

In addition, Dow Jones Newswires has reported police as commenting on at least two others buses exploding as well. However, these are yet to be confirmed.

Belinda Seabrook, and eye witness, reported to Press Association, the British news agency, "I was on the bus in front and heard an incredible bang, I turned round and half the double-decker bus was in the air."

She reported that the bus was packed with people: "It was a massive explosion and there were papers and half a bus flying through the air," she said.

Tony Blair has not released any official comment yet, but is scheduled to speak publicly at 12 p.m BST. He is currently hosting the world's most powerful leaders at Gleneagles, Scotland.

Official police reports have said that incidents were reported at Aldgate station near the Liverpool Street railway terminal, Edgware Road and King's Cross in north London, Old Street in the financial district and Russell Square in central London, near the British Museum.

London Ambulance Service said several vehicles had been dispatched to the area near Liverpool Street station.

A spokesperson for the City of London police said, "We believe there was some sort of explosion. There are some walking wounded at Aldgate. We are not sure of the scale of the incident. Reports are still coming in."

Simon Corvett, 26, on an eastbound train from Edgware Road station, said: "All of 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."

He concluded, "You could see the carriage opposite was completely gutted. There were some people in real trouble."