LONDON -- Britain's queen says the bomb attacks on London "will not change our way of life."

Queen Elizabeth II spoke Friday at the Royal London Hospital, which is among those treating victims of Thursday's bombings.

She said her country has "been here before" -- comparing the bombings to the Nazi bombings of World War II. But she said such attacks "simply reinforce our sense of community, our humanity and our trust in the rule of law."

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Slideshow: Terror In London

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London police said they've now confirmed 49 deaths in the blasts. The department confirmed the total after the city's police chief said all 13 bodies were recovered from a double-decker bus destroyed by one of the four bombs.

Metropolitan Police Commissioner Ian Blair said earlier that the death toll would likely pass 50 when bodies are retrieved from a subway train hit by a bomb in a tunnel.

London's mayor is urging residents to keep on "working and enjoying" their city as usual. Ken Livingstone says he plans to use the subway Monday "as normal."

Investigators said each of the bombs used in the three subway attacks and on the bus used less than 10 pounds of high explosives. Police say that means the bombs could have fit in a backpack.

More than 700 people were hurt in the bombings. At least 22 of the people who were wounded are hospitalized in serious or critical condition.

The country's top law enforcement official said all security officials are devoting their "total effort" to catching and punishing the bombers.

As for who did it, Blair said the coordinated series of attacks on subways and a double-decker bus have "all the hallmarks of al-Qaida."

An assistant police commissioner said each of the bombs contained less than 10 pounds of high explosives, so they were light enough to be carried in a bag or knapsack and were put on the floor of three subway trains. A top police official says the bomb used on a double-decker bus was either on the floor or a seat.

Officials refused to comment on a U.S. official's claim that investigators found evidence of timers in the debris, but the police commissioner said there's "absolutely nothing to suggest" suicide bombers were to blame.

Another top police official said investigators "are working under the most extreme circumstances." He said some officials are worried a subway tunnel could collapses on top of them, and bodies are still at that blast site as engineers study the area.

British Prime Minister Tony Blair blames Islamic extremists for the attacks. One group that claimed on a Web site that it carried out the attacks is warning Italy and Denmark about supporting U.S. campaigns in Iraq and Afghanistan.

But, counterterrorism officials are taking seriously the claim by the little-known al-Qaida group that it pulled off the deadly attacks.

A senior U.S. official has acknowledged that the Internet posting by a group called the "Secret Organization of al-Qaida in Europe" is considered potentially very credible.

Among the theories investigators are pursuing are whether the group may be linked to Iraqi terror chief Abu Musab al-Zarqawi, and whether the attacks could be the work of an existing terror group simply using a new name.

Making the al-Qaida link could be difficult because al-Qaida no longer has a "top-down" structure. U.S. experts said the terror organization is now a broader movement, drawing inspiration from Osama bin Laden's core group. A former Homeland Security official said that makes its members more dangerous and tough to track.

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The Day After: London Commuters Return

Police in London are gearing up for heightened security Friday and promising a manhunt for those responsible for Thursday's deadly rush-hour attacks.

Many of the subway trains are expected to be idle; others will have a heavy police presence.

So far, evidence suggests that some of the bombs were on timers.

Investigators are doubting that cell phones set off the London bombs -- as in Madrid last year -- because cell phones often don't work in the system's tunnels.

Meanwhile, an eyewitness to the bombings in London said he'll be haunted by the image of someone "whose face was totally black and pouring with blood."

Another said a subway car "was completely gutted" by one of the four blasts that hit Thursday morning.

Whatever the final death toll, it's the worst attack in London since World War II.

Belinda Seabrook was riding a bus to work in London when she heard what she called "an incredible bang." The double-decker bus behind hers had blown up -- one of four coordinated rush-hour explosions.

"I turned round," Seabrook said, "and half the double-decker bus was in the air."

Jay Kumar, who saw the explosion from his business nearby, said he saw "debris flying all over, mostly glass."

Doctors from the British Medical Association building rushed out to treat the wounded. BMA House was splattered in blood "and not much of the bus was left," said Dr. Lawrence Buckman.

On the subway, commuter Simon Corvett said he heard "this massive, huge bang." "All the windows shattered," Corvett said.

A security expert at St. Andrews University in Scotland agreed that the series of explosions have "all the trademarks of the al-Qaida network." He said the blasts on subways and a bus were "clearly aimed to cause casualties among the public."

Another expert at the university said London and its transportation network are "a very tempting target." Magnus Ranstorp added, "It's impossible to guard against this."

He said at least 10 to 20 people would have been involved in Thursday's bombings. He said any speculation of a connection to London being picked for the 2012 Olympics is "nonsense," because such an attack requires a lot of planning. Ranstorp said the bombings were likely intended to disrupt the Group of Eight talks going on in Scotland.

Survivors Share Stories

Michael Henning said he feels extremely lucky. He was just 10 feet from the first of Thursday's explosions targeting London's transit system, but survived with just a scratch to his eye.

Henning said he saw silver flashes of glass flying through the air, and a yellow flash before the train went dark, with people panicking and screaming. He said women on the train stayed calm and got things under control quickly.

Eamon Spelman was on another train that was bombed. He said he heard a woman screaming and saw other passengers blackened from soot. Spelman said his train seemed to dip and then come to a stop after the blast.

Other survivors were less fortunate. George Kolias said his 19-year-old daughter survived, but was gravely wounded with injuries to her chest and both legs. He said his daughter so far has not been able to remember anything that happened.

Prince Charles Praises Britons' Resilience

Prince Charles and his wife are praising the resilience of the British people following the deadly bombings.

They visited patients at St. Mary's Hospital in Paddington, close to a subway station where a bomb exploded on a train. The prince said his people are providing "a fantastic example of how to react to these kinds of tragedies."

His wife, the Duchess of Cornwall, said she's "very proud to be British."

Hospital worker Andrew Meyer was one of the first at the scene at the nearby blast. He told the royal couple that "the training kicked in for everyone."

Meyer said the patients "were so brave."