Below is a minute-by-minute timeline of the multiple explosions rocking London. All times are British Standard Time.
10:47 a.m.: Home Secretary Charles Clarke says London blasts cause "terrible injuries"
10:46 Police say serious casualties in London explosions, but no deaths confirmed
10:46 Witness to Britain's Sky News says second blast heard in Tavistock Square.
10:45 Police sources say a bomb is suspected in London bus explosion.
10:33 Police confirm at least three explosions on buses in central London.
10:25 Police confirm explosion on bus in central London in the area around Russell Square.
10:24 Scotland Yard says "multiple explosions" rock London.
10:14 News agencies report a bus has exploded in central London.
09:53 Metronet says the entire London subway network has been shut down.
Police says incidents are reported at the 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.
09:41 London Underground reports a second explosion at a subway station in northwest London.
09:33 Witnesses say London underground says services are suspended after "power surge."
09:27 Metronet, the subway maintenance company, says power surge has caused explosion in London tube station.
09:25 Police say "there are walking wounded" in London's financial district.
09:15 British transport police say a explosion is reported in London's financial district in the area near Liverpool railway station.