AP reports:

Half a dozen explosions rocked the London subway and tore open a packed double-decker bus during the morning rush hour Thursday. The blasts killed at least two people and injured scores in what a shaken Prime Minister Tony Blair said was a series of “barbaric” terrorist attacks.

Blair said it was clear the attacks were designed to coincide with the opening of the G-8 summit in Gleneagles, Scotland. The prime minister said the meeting of world leaders would continue but that he would return to London.

“Whatever they do, it is our determination that they will never succeed in destroying what we hold dear in this country and in other civilized nations throughout the world,” Blair said a day after London was awarded the 2012 Olympics.

Bloodied and bandaged witnesses reported panicked crowds fleeing the blast sites. A witness at the bus explosion said the entire top deck of the bus was destroyed.

God Bless Britain.

According to Sky News, a terrorist group linked to al Qaeda is claiming responsibility:

A terror group linked to al Qaeda has claimed it carried out a series of terror attacks on London that have left a number of people dead and hundreds injured.

Update, 7:38 am: According to Fox News, Sky News is reporting that there were reports of a suicide bomber on the bus that was blown up. This has not been confirmed, however.

Athena at Terrorism Unveiled comments here.

Instapundit round-up here.

751am EST. London police suspect at least a 15-man team involved in planning and execution of the bombings.

755am EST. Britain’s House condemnation: an “unspeakable act of evil and depravity.”

Sky News:

The entire Tube network has been shut down and police have confirmed blasts at four sites: Russell Square and Kings Cross Underground; Moorgate, Aldgate, and Liverpool Street Underground; Edgware Road Underground; and Tavistock Square where there has been a confirmed explosion on a bus.

One witness said the packed underground train he was on was 200 metres from King’s Cross when there was a huge flash.

The train stopped and people were using umbrellas to smash windows of the trains. Passengers were led out of the train by underground staff.

He added people were milling around King’s Cross covered in soot.

Timeline via CNN:

12:00 p.m.: British Prime Minister Tony Blair says the “barbaric” London blasts are terrorist attacks and were designed to coincide with the G8 summit in Scotland. He will return to London.

11:35 a.m.: London police chief tells Reuters news agency there are “indications of explosives” at one of the blast sites.

11:15 Police say there were at least six explosions in London.

11:15 European Union commissioner for justice and security affairs Franco Frattini tells reporters in Rome that the blasts in London are terrorist attacks.

11:10 Police say they have reports of two deaths and nine injuries at Aldgate East subway station.

11:07 All bus services have been suspended in London, news agencies report.

10.57 British Prime Minister Tony Blair will stay at the G8 summit in Scotland but says he will speak at midday.

10:47 Home Secretary Charles Clarke says multiple London blasts cause “terrible injuries.”

10:46 Police report serious casualties in London explosions, but no deaths confirmed.

10:46 Witness to Britain’s Sky News says second blast heard in Russell 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.

10:02 Scotland Yard says it is dealing with a “major incident.”

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.

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Updates:

Blair statement
Photos
Who did it?
Casualty reports
Looking homeward
Debunking the “Israel knew” myth
Reactions from the American left
DHS responds
Unity
Hitchens vs. moonbats
Britain’s breeding ground for suicide bombers