Emergency teams have responded to the blasts

Explosions have rocked London, killing at least two and wounding scores in what Prime Minister Tony Blair said was an apparent terrorist attack coinciding with a meeting of Group of Eight leaders in Scotland.

Witnesses on Thursday saw the top was ripped off a double-decker bus near Russell Square close to King's Cross train terminal and the twisted wreckage of another in Tavistock Square nearby.

Several underground railway stations were also hit.

Two people were killed in the rush-hour explosion at Aldgate East underground station, police said.

"[We can] confirm there were two fatalities at Aldgate East
station this morning," a police spokeswoman said.

"It is reasonably clear that there have been a series of terrorist attacks in London," Blair said at the summit. He added that he would return to London in the "next couple of hours".

A doctor at Aldgate underground station in the east of the financial centre of the city said at least 90 people were wounded at that location.

Transit shut down

The entire underground system was shut down and major thoroughfares were blocked off by police and ambulance services.

London's police chief Ian Blair said there were indications of explosives at one of the blast sites.

"We are aware that one of the sites certainly does contain indications of explosives," he told Sky Television. "We are
concerned that this is a coordinated attack."

There was no immediate claim of responsibility.

Covered in blood

People were seen streaming out of one underground station covered with blood and soot. Passengers were evacuated from stations across the capital, many in shock and with their clothes ripped to shreds, witnesses said.

Emergency services rushed to Aldgate East at 8.59am (0759 GMT).

"There were people streaming out of Aldgate station covered in blood," said witness Kate Heywood, 27, on her way to work.

A Reuters correspondent at Oxford Circus, at the heart of the system, heard an announcement over the public-address system saying: "A power outage has occurred London-wide. All train services are suspended."

Police sealed off large areas around other underground and mainline railway stations. Firefighters donned chemical protection suits before rushing into stations.

Half a dozen people with soot-blackened faces and dishevelled clothes sat on the floor at Russell Square station or stood in shock as police cordoned off the area and ambulance crews raced in, one witness said.