Two dozen leaders of Britain's Muslim community emerged from meeting with Tony Blair at the prime minister's Downing Street office on Tuesday, pledging solidarity with one another and the government to address the root causes of the suicide bombings that killed at least 56 people here and injured 700.

But even as they spoke of working together, many of the leaders -- the most prominent of Britain's Muslim moderates -- acknowledged strong disagreements among themselves, with the government and with radicals in their community over who or what is ultimately to blame for the attacks, which police say were carried out by four young British Muslims.

Is it the government's foreign policy, including Britain's participation in the Iraq war? Is it Islamic extremists who preach hate and condone violence? Or is it the Muslim community, which has failed to recognize and root out a cancer in its midst?

"We've gone through this shock period immediately after the bombing when we all reacted simultaneously to condemn it," said Nazir Ahmed, a Kashmiri Muslim and member of the House of Lords who attended Tuesday's session. "But now many people are confused as to how to deal with it."

Many Muslims blame the Iraq war, as do Britons in general. A poll in the Guardian newspaper Tuesday said two-thirds of the public believed there was a link between the bombings and the war, echoing the view in a briefing paper on Britain's security services issued by Chatham House, a prominent foreign policy research center in London.

Blair heatedly rejected such reasoning at a news conference after the meeting with the Muslim leaders, warning that it was perilously close to "the sort of perverted and twisted logic" used by terrorists.

"Of course, these terrorists will use Iraq as an excuse, or use Afghanistan," Blair said. "September 11, of course, happened before both of those things and then the excuse was American policy, or Israel," he added, referring to the 2001 attacks in the United States.

The anguished and impassioned argument among Muslims here over why four young people each strapped 10 pounds of explosives on their backs and blew up three subway trains and a double-decker bus is in part a debate about a minority community's relationship with larger British society. It is also a conflict over who speaks for the Muslim community, pitting moderates against extremists and, to an extent, Muslims from the Indian subcontinent against Arabs.

Yamin Zakaria, a Britain-based computer technician who publishes fiery manifestos on various Islamic and political Web sites, contends that the bombings were payback, not just for the Iraq and Afghanistan wars and the Israeli-Palestinian conflict but for a long series of atrocities committed by the West against the Muslim world. In his view, these include the slaughter of Muslims in Bosnia and the abuse of prisoners at Abu Ghraib prison in Iraq, the Bagram prison in Afghanistan and the Guantanamo Bay detention center in Cuba.

"It's human nature for people to fight back when they're attacked," he said. "You've slaughtered us for years, and no one hit back, but now that someone has, you cry foul."

Zakaria says the moderates who appeared at Downing Street are co-opted careerists and sellouts who do not speak for young Muslims. He is equally disdainful of those who want to see the bombers as brainwashed or disturbed.

One Muslim leader who was not invited to the Downing Street summit was Azzam Tamimi, a Palestinian academic who is a leader of the Muslim Association of Britain, a coalition of mostly Arab Muslim groups that was at the forefront of the antiwar campaign here. Tamimi is considered a moderate by many in the Arab community, but he also is a longtime supporter of Hamas, the radical Islamic group that rejects Israel's right to exist and is responsible for many of the suicide bombings there.

Tamimi says the London bombings were an act of barbarism. But he placed much of the blame on the government while at a rally of several hundred antiwar demonstrators on Sunday on a street off Russell Square, near the Piccadilly Line subway tunnel that was the scene of the worst of the attacks.

"See for yourself what you've done to the world," he said, addressing Blair and President Bush. "No matter how much we supervise our children, if the politicians do not revise their policies, it will not work."

In an interview afterward, Tamimi said he and other Muslims had done everything they could to combat the influence of radical preachers. He is part of the governing council that seized control of the Finsbury Park mosque in London at the behest of the authorities who said it had become a hotbed of extremism.

"The police asked for our help and we've cleansed Finsbury Park from the militants, and we ran a lot of risk," he said.

"But we've seen the commissioner of police, the prime minister and media put the blame on the Muslim community, as if the community could have prevented the bombings," he added. "If the government comes and shows me where I have failed, I will admit it, but we all know where the government has failed. I'm not absolving Muslims of any responsibility, but I'm saying the government is not helping us with its policies."

Several groups of Muslim clerics have issued fatwas, or religious decrees, against the London bombings, saying the acts were prohibited in Islam. But the fatwas have largely been silent about suicide bombings in Israel.

Tamimi asserts that the situation there is different. "A Palestinian has had his home bombed, he's had his children killed, his trees uprooted, and what he does is a legitimate response to oppression," he said. "But here we are in a democratic state. What these youngsters did in London is a crime against innocent people that is 100 percent forbidden in Islam."

About 1.3 million of Britain's estimated 1.8 million Muslims come from the Asian subcontinent -- Pakistan, Bangladesh and India -- and many have been here for two generations or more. While Indians are often prosperous, many Pakistanis and Bangladeshis have been stuck on the bottom rung of Britain's socioeconomic ladder. Even the most mainstream of organizations, such as the Muslim Council of Britain, express a sense of grievance against British society and complain about growing "Islamophobia."

Ahmed, the member of the House of Lords, says many Muslim parents believe their children are being brainwashed outside mosques and on university campuses by radicals, some of whom are Arabs.

Many of the Pakistani and Bangladeshi imams at mosques have moderate views, but their message doesn't get through -- often they deliver sermons and lessons in their native tongues, which many second- and third-generation young people do not understand.

"I was born in Pakistani Kashmir, but I don't understand every bit of Pakistani or Urdu," said Ahmed, 48, who came to England as a child. "So you can't expect my son to understand it, and my granddaughter understands nothing."

Mainstream Muslim leaders say they are discussing a variety of measures to make moderate Islam more relevant in the lives of young people. There is talk of requiring imams to preach at least parts of their sermons in English and of a new vetting system that would prevent radical clerics from taking over local mosques. The government is considering new statutes outlawing indirect incitement to terrorism and making it easier to deport foreign nationals who engage in it.

Some leaders said they feared such measures might exacerbate grievances and alienation and target Muslims for persecution. Others argued that the community in effect needs to look in the mirror before it worries about the actions of the outside world.

"We still have a lot of soul-searching to do," said Shahid Malik, a member of Parliament who represents Leeds. "We recognize we've got to do better at confronting these evil voices."

Iqbal Sacranie, center, secretary general of the Muslim Council of Britain, listens to statements outside Prime Minister Tony Blair's Downing Street office, where two dozen Muslim leaders met with government officials.