Update: Explosions rock London's transportation system

IDG News Service - A series of four explosions rocked London's public transport system this morning, killing at least 37 people and injuring hundreds of others. Mobile and fixed-line telephone networks were severely congested as panicked Londoners called relatives in the city, but there were no initial reports of more widespread communications damage.
The explosions tore through a double-decker bus, an underground station and other locations; British Prime Minister Tony Blair said the incidents appeared to be the work of terrorists.
London's public transport system was brought to a halt, with all underground stations and bus routes closed, according to several reports.
Representatives from local operators Orange PLC, O2 (U.K.) Ltd., T-Mobile U.K. Ltd., Vodafone Ltd. and British Telecommunications PLC all said they appeared to have suffered no damage to their infrastructure.
"Our network is not damaged, but we are experiencing a high volume of traffic, forcing customers to dial numbers a few times before they get a connection," a Vodafone spokesman said. "We're telling them they can expect some delay but they should keep trying."
Orange spokeswoman Sarah Taylor said, "No U.K. mobile phone operators have infrastructure in the Tube, so there are no base stations that can be affected in the underground system. "We have taken action to ensure maximum availability and improve traffic flow on our network in the London area."
BT saw a big surge in call volumes, congesting its networks and leading to delays in calls getting through, a spokesman said.
"We're asking people to only make essential calls," he said.
The news Web site of the British Broadcasting Corp., the state TV and radio company, continued to provide updates on events, although the site was slower to load than usual.
The main BBC Web site, which usually carries information about TV programs and entertainment, was unavailable for part of the morning. It came back online around midday in a slimmed-down form, with news headlines relating to the explosions and a warning not to call emergency services except in life-threatening situations.
There was no noticeable variation in the volume of Internet traffic through The London Internet Exchange Ltd., or Linx, which manages peering points in London for all major U.K. Internet service providers.
"With the Internet, there's been no effect," said Vanessa Evans, a spokeswoman for Linx, adding, "There's a lot of traffic flowing to the news sites, which are holding up very well."
Level 3 Communications Inc. and MCI Inc., two large providers of fiber-optic infrastructure for the Internet, claimed no problems.
"Our network is operating normally," saidan MCI spokeswoman in London. She declined to comment on where the company has cable.
A spokeswoman for Level 3 said the company's network was not affected in London City, also declining to comment on its cable routes.
The city's subway system is used by various telephone companies for their communication cables.

James Niccolai and Peter Sayer, of the IDG News Service contributed to this report, as did Reuters.