The causes of the explosions that apparently killed and wounded several people are yet unclear. The police is calling it a "major incedent"
From
The Guardian:
Many people were hurt today in a "major incident" on the London Underground as an apparent power surge caused at least two explosions, wounded commuters, and plunged London's transport network into chaos.
Union officials said their sources had told them there had been at least one explosive device on the Underground. A Sky News producer who was evacuated from Kings Cross and was walking towards Russell Square also reported seeing an explosion on a bus. He said the blast was caused by a bomb, and said people with "blood injuries" emerged from the bus. Scotland Yard could not immediately confirm the report.
British Transport police said several power surges had caused explosions across the network at Aldgate, Old Street, Kings Cross, Russell Square and Edgware Road. Emergency services crews attended wounded passengers outside Aldgate station, and there were reports of passengers covered in soot emerging from King's Cross. Travellers emerged from tunnels covered in blood.
Eyewitnesses reported "multiple casualties" at Liverpool Street. One witness who had been in a train at the time of the explosions reported seeing "bodies everywhere" in the carriages and limbs lying in on the floor. Emergency services reported several injuries. Scotland Yard declared the emergency a "major incident".
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