LONDON - More than 33 people were killed and hundreds injured after four bombs ripped through London's underground network and tore the roof off a bus during Thursday morning rush hour, police said.
No warning was given ahead of the attacks - the deadliest terrorist incident in the capital in recent years - and police said they were investigating claims that an Al-Qaeda-linked group had been involved.
In less than an hour, three bombs ripped through tunnels and trains in central London, killing 33 people, while a fourth bomb devastated a bus in the West End near Russell Square causing unknown fatalities, police said.
A top French official, meanwhile, said between 45 and 50 people were killed and some 1,000 injured.
"Four devices we believe were involved in today's incidents," the city's deputy police chief Brian Paddick told a joint press conference in London.
"The police service received no warning about these attacks," he said, noting that the authorities had also received no claims of responsibility.
"This clearly was a callous attack on purely innocent members of the public deliberately designed to kill and injure innocent members of the public."
He said that seven died in a first explosion at 8:51 am (0751 GMT) in an underground railway tunnel near Moorgate on the edge of London's financial district.
Five minutes later, a second bomb killed 21 near King's Cross and another five died at 9:17 am at Edgware Road station, when a bomb exploded on a train drawing into the station that blew a blast in the tunnel, affecting two more trains.
Finally, at 9:47 am, a bomb ripped through the top of a double decker bus at Upper Woburn square, near to Russell Square.
"There are fatalites in that incident but at the moment we cannot confirm the numbers," said Paddick.
Following the blasts, Russell Smith, assistant chief ambulance officer, said 45 people were being treated with serous or critical injuries, such as burns, amputations, chest and blast injuries and fractured limbs.
"We have also treated approximately 300 patients with minor injuries including lacerations, smoke inhalation, shock, cuts and bruises," he told reporters.
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