Injured passengers are escorted away from the Edgware Road Station in London’s underground following an explosion yesterday. Four blasts ripped through trains in the underground and tore apart a double-decker bus during the morning rush hour, killing at least 37 people and injuring more than 390 others. The entire  underground transport network and the central bus service were shut down. — AP

The death toll from the series of terrorist blasts in London rose to 33 while more than 360 people were injured, police said Thursday.

The almost simultaneous explosions rocked at least three London subway trains and ripped apart a double-decker bus during the morning rush hour, according to the police.

London's streets echoed with sirens and the entire bus and underground transport network was shut down just a day after an overjoyed city celebrating London's successful bid to hold the 2012 Olympics.

Police said there had been no warning.

SKY TV film showed a mangled red bus with its top collapsed. Bloody and bandaged witnesses said panicked crowds were fleeing as the blast rained glass and other debris onto the street.

"It was a massive explosion and there were papers and half a bus flying through the air," a panicked passenger was quoted by Skynews as saying.

Home Secretary Charles Clarke, Britain's top law enforcement officer, confirmed four explosions: three in the subway system and one on the bus at Russell Square near the British Museum. He said there were "terrible injuries".