WASHINGTON: A new poll of American Muslims reveals a group that is better assimilated, more content and less politically polarized than counterpart Muslim populations in Western Europe - but also smaller in number than some Muslim groups had estimated.

For the survey, the Pew Research Center interviewed nearly 60,000 respondents - in Arabic, Urdu, Farsi or English - to find a representative sample of 1,050 respondents, for what appears to be one of the more rigorously complete looks at a population that is not well understood.

As a whole, the poll found a largely content and hard-working U.S. Muslim population, and one that is fast assimilating. Though 4 in 10 have arrived since 1990, a large proportion say their closest friends are non-Muslims. Their incomes are close to the national average. Even more than the general public, they say they believe that by working hard they can get ahead.

Eight in 10 said they were "very happy" or "pretty happy" with their lives.

But young American Muslims - those under 30 - were more accepting of extremism. They were far more likely than their older counterparts to see themselves as Muslims first rather than as Americans first.

Still, U.S. Muslims were less likely to see themselves as Muslim first than their counterparts in Western Europe.

Six percent of the U.S. Muslim population said suicide bombings were justifiable sometimes or always in defense of Islam, but among the young, the figure was 15 percent.

The poll also found African-American Muslims, many of them converts to Islam, to be more disaffected, more likely to complain of discrimination, and more politically polarized than other American Muslims.

African-American Muslims were more than three times as likely as Muslim immigrants - the largest numbers coming from Pakistan, Iran, India and Lebanon - to express dissatisfaction with national conditions.

While only 5 percent of American Muslims expressed even slightly favorable opinions of Al Qaeda, foreign-born U.S. Muslims were far more likely than African-American Muslims - by 63 percent to 36 percent - to express a very unfavorable opinion of the terrorist group.

Over all, U.S. Muslims were far more likely than Muslims in Europe or the Middle East to see a possibility for Israeli-Palestinian coexistence. Their views were close, on this question, to those of the general American public.

While most U.S. Muslims expressed largely positive views of American society, a majority said life had grown more difficult since the Sept. 11 attacks. One in four said they had been the victims of discrimination in the United States. This was particularly true of the native-born Muslims, about half of whom are black Americans.

American Muslims were much more concerned about the rise of Islamic extremism than were Muslims elsewhere. Fifty-one percent said they were very concerned about the rise of extremism around the world, a much larger proportion than expressed by Muslims in Western Europe and the Middle East.

In France, Germany and Spain, only about one-third of Muslims said they were very concerned about the global rise of Islamic extremism.

Still, skepticism among American Muslims about the U.S.-led fight against terrorism, and about the Iraq and Afghanistan wars, runs deep. Only 26 percent saw the U.S. fight against terrorism as a sincere effort to reduce terrorism, less than half the number in the general public.

Muslim Americans opposed the Iraq war by more than six to one, and opinions of the Afghanistan war were also largely negative. Just 15 percent approve the way President George W. Bush has handled his job.

Because the U.S. census does not ask about religious affiliations, there has long been a debate about the number of Muslims in the country. Estimates have ranged from around one million, in a 2001 survey by City University of New York, to six or seven million, by some Arab and Muslim groups.

The Pew estimate, based on its survey data and extrapolations of Census Bureau data, was 2.35 million, about 0.6 percent of the U.S. population. Because interviews were conducted by landline phone, and younger people may tend to have only cellular phones, Pew conceded that the total might be slightly low.