WASHINGTON (AP) _ One in four younger U.S. Muslims say suicide bombings to defend their religion are acceptable at least in some circumstances, though most Muslim Americans overwhelmingly reject the tactic and are critical of Islamic extremism and al-Qaida, a poll says.
The survey by the Pew Research Center, one of the most exhaustive ever of the country's Muslims, revealed a community that in many ways blends comfortably into society. Its largely mainstream members express nearly as much happiness with their lives and communities as the general public does, show a broad willingness to adopt American customs, and have income and education levels similar to others in the U.S.
Even so, the survey revealed noteworthy pockets of discontent.
While nearly 80% of U.S. Muslims say suicide bombings of civilians to defend Islam can not be justified, 13% say they can be, at least rarely.
That sentiment is strongest among those younger than 30. Two percent of them say it can often be justified, 13% say sometimes and 11% say rarely.
``It is a hair-raising number,'' said Radwan Masmoudi, president of the Washington-based Center for the Study of Islam and Democracy, which promotes the compatibility of Islam with democracy.
He said most supporters of the attacks likely assumed the context was a fight against occupation _ a term Muslims often use to describe the conflict with Israel.
U.S. Muslims have growing Internet and television access to extreme ideologies, he said, adding: ``People, especially younger people, are susceptible to these ideas.''
Federal officials have warned the U.S. must guard against homegrown terrorism, as the British suffered with the London transit bombings of 2005.
Even so, U.S. Muslims are far less accepting of suicide attacks than Muslims in many other nations. In Pew surveys last year, support in some Muslim countries exceeded 50%, while it was considered justifiable by about one in four Muslims in Britain and Spain, and one in three in France.
``We have crazies just like other faiths have them,'' said Eide Alawan, who directs interfaith outreach at the Islamic Center of America in Dearborn, Mich., one of the nation's largest mosques. He said killing innocent people contradicts Islam.
Andrew Kohut, Pew director, said in an interview that support for the attacks represented ``one of the few trouble spots'' in the survey.
The poll briefly describes the rationales for and against ``suicide bombing and other forms of violence against civilian targets'' and then asks, ``Do you personally feel that this kind of violence is often justified to defend Islam, sometimes justified, rarely justified, or never justified?''
The question did not specify where a suicide attack might occur, who might carry it out or what was meant by using a bombing to ``defend Islam.''
Those of all ages backing at least some suicide attacks were about evenly divided between men and women, with support stronger from those who were U.S.-born and less educated, and those who attend mosques at least weekly.
In other findings:
_Only 5% of U.S. Muslims expressed favorable views of the terrorist group al-Qaida, though about a fourth did not express an opinion.
_Most said they are concerned about a rise in Islamic extremism in the U.S. and around the world.
_Only 40% said they believe Arab men carried out the attacks of Sept. 11, 2001.
_By six to one, they say the U.S. was wrong to invade Iraq, while a third say the same about Afghanistan _ far deeper than the opposition expressed by the general U.S. public.
_Just over half said it has been harder being a U.S. Muslim since the 9/11 attacks. Nearly a third of those who flew in the past year say they underwent extra screening because they are Muslim.
_Forty-seven percent said they consider themselves Muslim first, rather than American. Forty-two percent of Christians and 62% of white evangelical Protestants identified themselves primarily by their religion in earlier surveys.
The survey estimates there are roughly 2.35 million Muslim Americans. Among adults, two-thirds are from abroad while a fifth are U.S.-born blacks.
By law, the Census Bureau does not ask about people's religions.
Telephone interviews were conducted with 1,050 Muslim adults from January through April, including in Arabic, Urdu and Farsi. Subjects were chosen at random, from a separate list of households including some with Muslim-sounding names, and from Muslim households that had answered previous surveys.
The margin of sampling error was plus or minus 5 percentage points.