In all, 52 percent of Muslim-Americans surveyed said their group is singled out for terrorist surveillance. Almost as many — 43 percent — reported they had personally experienced harassment in the past year, according to the poll released Tuesday.

That 43 percent share of people reporting harassment is up from 40 percent in 2007, the first time Pew polled Muslim-Americans.

Asked to identify in what ways they felt bias, about 28 percent said they had been treated or viewed with suspicion by people, while 22 percent said they were called offensive names. About 21 percent said they were singled out by airport security because they were Muslim, while another 13 percent said they were targeted by other law enforcement officials. Roughly 6 percent said they had been physically threatened or attacked.

On the other hand, the share of Muslim-Americans who view US anti-terror policies as “sincere” efforts to reduce international terrorism now surpasses those who view them as insincere — 43 percent to 41 percent. Four years ago, during the presidency of George W. Bush, far more viewed US anti-terrorism efforts as insincere than sincere — 55 percent to 26 percent.

The Associated Press reported last week that with CIA guidance, the New York Police Department dispatched undercover officers into minority neighborhoods, scrutinized imams and gathered intelligence on cab drivers and food cart vendors, jobs often done by Muslims. It is now common in US mosques for Muslims to preface public remarks by saying that they know the government is eavesdropping but Muslims have nothing to hide. Still, one factor behind the somewhat upbeat sentiment of Muslim-Americans is the 2008 election of Obama, who pledged to improve relations with the Muslim world. Muslim-Americans who vote largely identify themselves as Democrats, and fully 76 percent of those surveyed say they approve of Obama’s job performance, compared with 15 percent in 2007 who approved of Bush’s performance.

Regarding possible terror risks, about 21 percent of Muslim-Americans say there is “a great deal” or “a fair amount” of support for extremism in their communities, according to the Pew survey. About 81 percent of Muslim-Americans separately say suicide bombings and other forms of violence against civilians are never justified in order to defend Islam, and growing numbers also express an unfavorable view of Al-Qaeda — 81 percent compared with 68 percent in 2007.

The vast majority of Muslim-Americans — 79 percent — rate their communities as either “excellent” or “good” places to live in, even among many who reported an act of vandalism against a mosque or a controversy over the building of an Islamic center in their neighborhoods.

The survey by the Pew Research Center, one of the most exhaustive ever of the country’s Muslims, finds no signs of rising alienation or anger among Muslim-Americans.

The findings offer an uncommon portrait of the Muslim-American community, which Pew estimates at roughly 2.75 million, or nearly 1 percent of the US population. By law, the Census Bureau does not ask about people’s religions, so extensive details about Muslim-American views, their size and demographics as a group are not widely known.

Mostly foreign-born immigrants, Muslim-Americans are significantly younger, more likely to be male and more racially diverse than the public as a whole. They express a broad willingness to adopt US customs and are just as likely as the rest of Americans to hold a college degree.

When asked to choose, nearly half of Muslims in the US say they think of themselves first as Muslim, rather than as American. Roughly 60 percent say that most Muslims come to the US to adopt the American way of life and see no conflict between being a devout Muslim and living in a modern society.

Foreign-born Muslims in the US come from at least 77 different countries, led by Pakistan, Iran, the Palestinian territories, Bangladesh, Yemen, Jordan and Iraq. About 70 percent of foreign-born Muslims report they are now naturalized US citizens, higher than the 47 percent rate for the broader immigrant population in the US

The Pew survey is based on telephone interviews with 1,033 Muslims in the US, conducted in English, Arabic, Farsi or Urdu from April 14 to July 22. 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.