Update: London Terror Blasts

London police said four bombs on the city's subway and bus lines went off during the morning commute killing at least 33 people and wounding hundreds.

According to insurance representatives in London, the city's train and bus services are self-insured. Other insurance executives have said it is too early to assess the impact of the bombings on the insurance industry.

Brian Paddick of the London Metro Police said in a news conference today that three subway lines and one bus were bombed. So far, 33 people have been confirmed dead in the subway line bombings. All tolled, 345 people were injured, 45 seriously. Police said there were fatalities in the bus bombing but could not confirm how many died at the time.

Mr. Paddick said there was no warning given before the explosions, and no credible claim of responsibility.

"We are shocked by what has happened, but not surprised," Mr. Paddick said.

The first blast occurred on a subway car at 8:51 a.m., London time (3:51 a.m. EDT), with the other three occurring within minutes of one another. The bus explosion took place at 9:47 a.m., London time.

The explosion occurred as leaders from the industrialized nation were beginning their G-8 conference in Gleneagles, Scotland, hosted by British Prime Minister Tony Blair. Mr. Blair has left the conference and returned to London.

In the United States, Secretary of Homeland Security Michael Chertoff said he has raised the security level from "Yellow" (elevated) to "Orange" (High) for the nation's mass transit system. He called upon commuters to be more alert to their surroundings and for a greater police presence at the nation's train and bus stations. The alert also means greater surveillance including K-9 units and searches.

"This is a measured and appropriate response to what has happened overseas," he said during a news conference.