A series of four explosions rocked London's public transport system Thursday morning, killing at least 33 people and injuring many others.
In a press conference late afternoon local time, the police reported that three explosions hit the city's Underground rail system, and one hit a double-decker bus. The police confirmed 33 deaths, including 21 at the Liverpool Street Underground station. The death toll is likely to rise, as the police could not confirm the number of deaths in the bus explosion. Some media reports put the death toll at more than 40.
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 police reported 45 serious injuries, with about 345 total injured. They did not immediately release information on suspects.
Britain's Prime Minister Tony Blair said the incidents appeared to be the work of terrorists.
In a statement, Blair said it appeared clear that the bombings were timed to coincide with the start of the so-called G8 talks in Gleneagles, Scotland, where the leaders of the world's wealthiest eight nations are meeting this week.
"Each of the countries round that table have some experience of the effects of terrorism and all the leaders, as they will indicate a little bit later, share our complete resolution to defeat terrorism," he said.
A previously unknown group called the "Secret Group of al Qaeda's Jihad in Europe" has claimed responsibility for the attacks, according to some press reports.
"London has always been a terrorist target. We're clearly shocked at what happened today, but we're not surprised," said Metropolitan Police spokesman Brian Paddock.
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, O2 (UK), T-Mobile UK, Vodafone, and British Telecommunications. 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 at www.bbc.co.uk, 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. (Linx), which manages peering points in London for all major U.K. ISPs (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 and MCI, two large providers of fiber-optic infrastructure for the Internet, claimed no problems.
"Our network is operating normally," said an 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.