Acting on a tip, police detained the men, aged 26 to 50, under the Terrorism Act at a cleaning depot in central London after receiving information about a possible threat. The men were being questioned at a London police station and have not been charged. Police said an initial search of that business and other properties did not uncover any hazardous items.

Police said the five were arrested "on suspicion of the commission, preparation or instigation of acts of terrorism." Police said a sixth man -- a 29-year-old -- was arrested later in the day at his home but no other details were immediately available.

The pope's visit has divided opinion in officially Protestant, highly secular Britain. The trip has been overshadowed by disgust over the Catholic Church's clerical abuse scandal and opposition from secularists and those opposed to the pope's stances against homosexuality and using condoms to fight the virus that leads to AIDS.

The detained suspects worked for a contractor on behalf of Westminster Council, the authority responsible for much of central London. Benedict spent much of the afternoon in Westminster Hall and Westminster Abbey; the depot were the men were arrested is responsible for cleaning another part of London that the pope is not due to visit, however, police said.

Police confirmed that some of the suspects were thought to be from outside Britain but declined to comment on media reports they were of Algerian origin.

One street sweeper at the depot, who requested anonymity because he was not authorized to speak to the media, said at least one of those arrested was Algerian, and that he believed all five arrested in the morning were from North Africa.

Veolia Environmental Services, the cleaners' company, had no immediate comment on the arrests.

At the scene of the arrests in Chiltern Street, close to London's Madame Tussauds' tourist attraction, police cordoned off part of the road, removing items from the Veolia depot and examining nearby garbage cans.

The pope's security on this trip has been visibly higher than on previous foreign trips, and Vatican officials have acknowledged that Britain represents a higher security threat than the other European countries Benedict has visited this year, including Portugal, Malta and Cyprus.

News of the arrests came as the pope was meeting representatives of other religions, including Muslims and Jews, and stressing the need for mutual respect, tolerance and freedom. The Vatican said the pope was informed of the arrests and was pleased he could stick to his schedule.

"We have complete trust in the police," Vatican spokesman Rev. Federico Lombardi told reporters. "The police are taking the necessary measures. The situation is not particularly dangerous."

"The pope is happy about this trip and is calm."

Hours after the arrests, Benedict met with the Archbishop of Canterbury Rowan Williams, the spiritual leader of the worldwide Anglican Communion, at his London residence. The meeting came amid new tensions following Benedict's unprecedented decision last year to make it easier for Anglicans opposed to the ordination of women bishops to convert to Catholicism.

Benedict and Williams greeted each other warmly. Benedict said flat-out he had no intention of speaking of difficulties "that are well known to everyone here." Rather, he stressed the need for Christians to work together and bring a greater sense of virtue into public discourse.

Williams, who has not hidden his dismay over the Vatican's invitation to conservative Anglicans, also stressed the ongoing effort to bring the two churches back together, saying each side was "made less by the fact of our dividedness."

He praised Benedict for his constant call to bring faith into public policy -- a theme Benedict explored further in a speech in Westminster Hall attended by former Prime Ministers Margaret Thatcher, John Major, Gordon Brown and Tony Blair, who recently converted to Catholicism.

Benedict praised Britain's democracy as a model worldwide for valuing freedom of speech and respect for law.

But he lamented that religion, particularly Christianity, was increasingly being marginalized from political decision-making, citing as an example the global financial crisis, which he has blamed on an absence of strong ethical foundations in economic policy.

"There are those who would advocate that the voice of religion be silenced, or at least relegated to the purely private sphere," he said. "There are those who argue that the public celebration of festivals such as Christmas should be discouraged, in the questionable belief that it might somehow offend those of other religions or none."

"These are worrying signs of a failure to appreciate not only the rights of believers to freedom of conscience and freedom of religion, but also the legitimate role of religion in the public square."

Benedict travels with his own security detail, headed by chief papal bodyguard Domenico Giani. Benedict's white, bulletproof Popemobile is flanked by eight to 10 dark-suited bodyguards who jog alongside, scanning crowds for potential threats.

There have been no major known attempts against Benedict during his five-year papacy, although he was knocked down at Christmas Eve Mass in 2009 by a mentally unstable woman who jumped the security barricade inside St. Peter's Basilica. In 2007, a man jumped the barricade in St. Peter's Square and grabbed the pope's vehicle before being pushed to the ground by guards.

Benedict's predecessor Pope John Paul II was wounded in an assassination attempt in 1981 in St. Peter's Square. Police in the Philippines also disrupted an alleged plot to assassinate John Paul in Manila in 1995.

Benedict was nearly 30 minutes late for his first event Friday morning; the Vatican attributed the delay at the time to logistical problems. It wasn't known if the arrests contributed to the delay.

The pope was then given a boisterous welcome by thousands of cheering Catholic schoolchildren at St. Mary's University College in London, where he urged young people to ignore the shallow temptations of today's "celebrity culture."

Benedict also told their teachers to make sure to provide the children with a trusting, safe environment -- the second time in as many days that he has referred to the church sex abuse scandal. On Thursday, the pope acknowledged that the Roman Catholic Church had failed to act quickly or decisively enough to remove pedophile priests from ministry.

"Our responsibility toward those entrusted to us for their Christian formation demands nothing less," Benedict said. "Indeed, the life of faith can only be effectively nurtured when the prevailing atmosphere is one of respectful and affectionate trust."

Polls in Britain indicate widespread dissatisfaction with the way Benedict has handled the sex abuse scandal, with Catholics nearly as critical of him as the rest of the population.

Outside the London university hall, some 4,000 young students, outfitted in prim school uniforms and waving small white-and-yellow Holy See flags, serenaded the pontiff Friday with gospel hymns and songs.

The students, from England, Scotland and Wales, gave Benedict a tie-dyed stole and three books tracing the history of the Catholic Church in Great Britain. The 83-year-old Benedict appeared relaxed and happy, gently greeting children and kissing them on the head.

In a surprise move, Becky Gorrod, 39, who had been standing outside the gates of St. Mary's holding her 8-month-old daughter Alice, was ushered in to meet the pontiff as the crowd cheered.

"My husband's never going to believe me," Gorrod told journalists. "They opened the car door, and the pope got out. Then the (pacifier) fell out of Alice's mouth, and the pope bent down and picked it up! The pope! How mad is that?"

She said the pope then kissed Alice on the forehead.

A few blocks away, about 30 people protested, holding up inflated condoms and posters. "Condoms are not crimes," read one. Another read: "Science flies you to the moon: religion flies you into buildings."

Michael Clark, 60, said he was protesting because he was gay and annoyed that the pope's visit was expected to cost British taxpayers 12 million pounds ($18.7 million) for security.

"That means it's being supported by taxpayers and people who may not have the same ideas," Clark said. "Sexuality is not evil."

Benedict began his four-day U.K. state visit on Thursday, greeted by Queen Elizabeth II at Holyroodhouse Palace in Edinburgh, Scotland. He wraps it up Sunday in Birmingham when he beatifies the 19th century Anglican convert Cardinal John Henry Newman.

Catholics are a minority in Britain at 10 percent, and until the early 19th century they endured harsh persecution and discrimination and were even killed for their faith. King Henry VIII broke with Rome in the 16th century after he was denied a marriage annulment.

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Associated Press Writers David Stringer, Raphael G. Satter, Jill Lawless, Jennifer Quinn and Danica Kirka contributed to this report.

Pamela Geller furiously rejects any responsibility for the threatening, racially charged tenor of yesterday's incident. But should anti-Muslim protesters here emulate her thuggish allies in the United Kingdom, nobody should be surprised when disorder and even bloodshed follow.

Geller has declared herself a proud supporter of the English Defence League, a far-right street movement that sprang up in the United Kingdom earlier this year to protest planned construction of mosques and to stoke fear of Islam more broadly. She isn't troubled by the EDL's shadowy leadership, nor by its connections with English fascist organizations and propensity for violence against bystanders, counter-protesters and the police. Last May she wrote:

Free people should support the English Defence League in its efforts to stand for England and the West against the belligerent invaders and Islamic imperialists.

The EDL is routinely smeared in the British media, as the Tea Party activists are smeared in the U.S. media. The corrupt, biased media defames any group, person, or organization standing against Islamic supremacism. They tar, feather, and destroy the good name of good people who stand for life, liberty, and individual rights. Libel and slander like "racist," "fascist," "bigot," etc. color every news report of every counter-jihad action. The quisling media is the propaganda arm of jihad. It's despicable. There is nothing racist, fascist, or bigoted about the EDL.

The brutal bigotry of the EDL and its leaders was thoroughly documented by the Guardian in an undercover investigation conducted over four months and published last May with copious video footage. The Guardian report includes the voice of an EDL leader boasting about what might happen when his followers overpower the police and confront counter-protesters. "If them barriers break one day and our lads get through," he said, "they will murder them all."

While laying siege to the city of Dudley last month -- in a successful effort to stop construction of a mosque there -- EDL hooligans stormed through town, smashing shop windows and vehicles and fighting riot police. The Birmingham Mail newspaper reported on July 19 that "violence flared as police attempted to get the [EDL] protesters back onto buses at the end of the demonstration, with EDL supporters throwing bricks and metal security fences at riot police. 

None of this fazes Geller, who declared her support in July for a Jewish auxiliary of EDL (which was promptly denounced by mainstream Jewish leaders in the U.K.). "I am proud to announce the formation of the Jewish Division of the EDL," she wrote on July 18. "Righteous."

So much for the anti-mosque agitator's proclaimed devotion to nonviolence and human rights. What occurred last Sunday may be the harbinger of far worse to come.  

Obama sought a diplomatic tone in response, saying the U.S. would "welcome any additional information," and made clear he wanted it. Beyond the lingering anger, the case swirls anew with interest because of its possible links to BP, the company facing huge fallout in the United States for causing the Gulf oil spill.

"I think all of us here in the United States were surprised, disappointed and angry about the release of the Lockerbie bomber," Obama said in a short news conference dominated by the topic. Yet he added: "The key thing to understand here is that we've got a British prime minister who shares our anger over the decision. And so I'm fully supportive of Prime Minister Cameron's efforts to gain a better understanding of it."

At issue is Libyan Abdel Baset al-Megrahi, who was convicted for the 1988 bombing of a jet over Lockerbie, Scotland that killed 270 people, most of them American. The Scottish government released the cancer-stricken man on compassionate grounds last year, igniting outrage on both sides of the Atlantic.

Bringing the matter to the fore again are accusations that BP sought the release of the convicted bomber as part of efforts to seek access to Libyan oil fields; BP has acknowledged that it urged the British government to sign a prisoner transfer agreement with Libya but says it never specified al-Megrahi's case.

"Any lobbying they might have done is an issue for BP, and an issue that they should explain themselves," Cameron said flatly.

The British leader said, though, that he has not see anything to suggest that the Scottish government was swayed by BP.

The issue overshadowed a broader agenda that Obama and Cameron discussed in the Oval Office and over lunch before addressing reporters. The 43-year-old Cameron, a few years younger than Obama, took power in May and leads a coalition government of his Conservative Party and the smaller Liberal Democrats.

He and Obama displayed a united front on the threat of a nuclear-armed Iran, the need for direct Middle East peace talks and the fight in Afghanistan.

And in a tradition that seems to roll from one new president to the next prime minister, Obama and Cameron also went out of their way to be friendly.

They joked about beer and how to get their children to clean their rooms, called each other by their first names and hailed the "special relationship" that has linked the allied nations in war and peace. "The United States has no closer ally and no stronger partner than Great Britain," Obama declared.

But just ahead of Cameron's arrival in Washington, Secretary of State Hillary Rodham Clinton requested that the Scottish and British governments review exactly what happened in al-Megrahi's release. That seemed to go nowhere with Cameron, who said: "I don't think there's any great mystery here."

"There was a decision taken by the Scottish Executive -- in my view, a wholly wrong and misguided decision, a bad decision, but their decision, nonetheless," he said. "That's what happened, and I don't think we need an extra inquiry to tell us that that's what happened."

Even Obama said whatever information emerges will likely lead to the same conclusion: "It was a decision that should not have been made," he said.

Al-Megrahi served eight years of a life sentence. He was released and returned to Libya in August 2009 after doctors said he had only three months to live, but a doctor now says he could live for another decade.

Cameron did say that his government would cooperate with the inquiry being pursued by the U.S. Senate Foreign Relations Committee. And the matter shows little sign of quickly fading away as long as BP is in the mix. The British prime minister said that he and Obama discussed the company at length.

In front of reporters, Cameron was notably more defensive of the British company than Obama. Cameron said BP must be responsible for responding to the Gulf disaster it caused and compensating victims, but he also described BP's success as vital to the British and U.S. economies and to thousands of workers.

"Let us not confuse the oil spill with the Libyan bomber," Cameron said, a point he emphasized more than once.

On the economy, two leaders are taking different approaches to budget-cutting amid a fragile economic recovery.

Cameron's government has imposed stringent spending cuts, while the Obama administration favors eventual deficit reduction -- but does not want to halt stimulus spending too quickly for fear of plunging the U.S. back into recession.

Obama downplayed the differences, saying countries approach cutting their debts in their own ways and at their own pace. With domestic pressures mounting to cut deficit spending, Obama said he is committed to taking on the government's systemic debt problems.

"This isn't just an empty promise," he said.

But the Journal isn’t telling the truth. BP is not capable of writing a letter or "saying" anything, "submitting" anything, or "stepping up its efforts."

You see, BP is not a person.

Like any other corporation, BP is a collection of contracts. The collection includes employment contracts -- with people who are paid to be executives, with others who are expert in how to plug holes a mile below the surface of the Gulf, and with lots of workers. There are contracts with BP’s creditors, who expect to be paid on time. There are contracts with numerous suppliers, with other companies like Halliburton, with the owners of tankers. And there are contracts with the U.S. government, which has leased part of the Gulf to BP for drilling.

At the center of this web of contracts are BP's shareholders, who legally own BP. That means they own BP's assets -- oil reserves under land or ocean bed that BP as a corporation is entitled to, its physical capital (rigs, tankers, and so on), and its financial assets, which amount to tens of billions of dollars.

BP's shareholders (including pensioners who have shares of pension funds, small investors who own shares in mutual funds, and major investors, all over the world) are interested in only one thing -- maximizing the value of their shares. Over the last month and a half, these shareholders have gotten clobbered. Some have sold out to other investors who believe BP's share values will rise. Others are holding on in the hope that they will.

It's impossible for BP to commit to doing anything because BP is not a human being capable of making commitments. BP's executives (like Tony Hayward) work for BP's shareholders. They can be replaced by BP's shareholders if BP’s shareholder aren’t satisifed with their performance. Or, more likely, BP's shareholders can sell out to major investors who will then replace BP’s executives if they don’t like the job they're doing.

It doesn't matter if Tony Hayward is called to the White House. It doesn't matter that President Obama says he'd like to fire him. Hayward's first responsibility is to BP's shareholders.

Some Americans are also be BP shareholders, but their interests as U.S. citizens aren’t represented in their roles as shareholders. Their citizenship interests are represented by our government, headed by the president.

As citizens, we want the hole in the Gulf plugged up as fast as possible, we want the spill contained, and we want everything cleaned up and damages paid -- no matter how much it costs BP's shareholders. But if we're BP shareholders, we want to minimize all such expenditures -- including our long-term liabilities.

Get it? There's no conflict between Britain and the United States. The conflict is between two kinds of interests -- shareholder interests and citizen interests.

And unless or until citizenship interests predominate in the Gulf -- unless or until BP's shareholders are forced by law to part with their assets to ensure the safety of the American public -- shareholder interests will come first. That’s why it's so important for the administration (and, if necessary, Congress) to take steps to put BP America under temporary receivership, establish an escrow fund of at least $10 billion that BP must pay into, and whatever else is necessary to trump shareholder interests.

Officers found Bird's body in woods near the Lake District village of Boot. Hyde said two weapons were recovered from the scene.

The shootings occurred in the town of Whitehaven and nearby Seascale and Egremont, about 350 miles (560 kilometers) northwest of London. The area is popular with hikers and vacationers.

Health service spokesman Nigel Calvert said three of the injured were in a critical condition in the hospital.

Hyde said there were 30 separate crime scenes. Witnesses described seeing the gunman driving around shooting out the window of his car. His victims included a woman on a bicycle, a farmer in his field and at least two fellow taxi drivers.

Barrie Walker, a doctor in Seascale who certified one of the deaths, told the BBC that victims had been shot in the face, apparently with a shotgun.

Witness Alan Hannah told the Whitehaven News that he saw a man with a shotgun in a car near a taxi stand in Whitehaven. Photos showed a body, covered in a sheet, lying in a street in the town.

"This kind of thing doesn't happen in our part of the world," local lawmaker Jamie Reed told the BBC. "We have got one of the lowest, if not the lowest, crime rates in the country."

Multiple shootings in Britain are rare. In 1987, gun enthusiast Michael Ryan killed 16 people in the English town of Hungerford. In 1996, Thomas Hamilton killed 16 children and a teacher at a kindergarten in Dunblane, Scotland.

Glenda Pears, who runs L&G Taxis in Whitehaven, said one of the victims was another taxi driver who was a friend of Bird's.

"They used to stand together having a (laugh) on the rank," she said. "He was friends with everybody and used to stand and joke on Duke Street."

Sue Matthews, who works at A2B Taxis in Whitehaven, said Bird was self-employed, quiet and lived alone.

"I would say he was fairly popular. I would see him once a week out and about. He was known as 'Birdy,'" she said.

"I can't believe he would do that -- he was a quiet little fellow."

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Associated Press Writers Jill Lawless and Andrew Khouri in London contributed to this report.