Explosions in London Bus, Underground

The explosion on the double-decker London bus appears to have taken place outside the British Medical Association on Tavistock Square in central London on Thursday morning. Details remained unclear, and there was no information as to the cause of the blast.

Earlier, London's entire underground railway network was suspended after an explosion around 9:00 a.m. local time. A spokesman described the blasts, which left several people injured, as a "major incident." The authorities said it was possibly caused by a power surge.

The chaos came a day after the British capital was chosen to host the 2012 Olympics.

Police evacuated several mainline railway and underground stations after a blast near Liverpool Street Station, which serves London's financial district, and a separate incident in the west of the capital.

"We believe there was some sort of explosion. There are some walking wounded at Aldgate," a police spokesman said, referring to an underground station near Liverpool Street. "We are not sure of the scale of the incident. Reports are still coming in."

A spokesman for London Underground said a second incident had taken place at Edgware Road station in west London.

Emergency vehicles rushed to the scene to deal with the confusion.

Witnesses on Sky television were quoted as saying people streamed out of some of the stations covered in soot, some in tears, many visibly shocked.

One of the evacuated stations was Stratford, which will be a key transport link for the site of the Olympic Games.