Paramedics arrive on  scene at Edgware Road Tube Station in London following explosion, Thursday

British authorities say London's entire public transport system has been shut down after several explosions shook the city's bus and underground railway network, Thursday.

British Home Secretary Charles Clarke says the blasts had caused terrible injuries, but gave no specific figures. Police later confirmed at least two deaths.

London's police chief said authorities have found indications of explosives in the area of at least one site and expressed concern that the explosions were part of what he called a coordinated attack.

Authorities sealed off areas around the train stations following the blasts that shook the subway system at the height of the morning rush hour.

Reports say explosions shook at least three city buses shortly after the subway blasts. One of them ripped off the top of a double-decker bus.

Prime Minister Tony Blair, who is attending the Group of Eight summit in Scotland, is to address the nation shortly.

The chaos comes a day after the British capital was chosen to host the 2012 Olympic Summer Games.

Some information for this report provided by AP.