The evening at Dar Al Hijrah Islamic Center began cordially, with a dinner of lamb and rice for the head of the FBI's Washington field office and seven of his agents. But the mood grew tense after the guests were escorted to the prayer room of the Falls Church mosque for a town hall meeting.

"We need to know the definition of terrorism and terrorists," one mosque member told the agents. Why, asked another, had the FBI raided a Muslim organization that had helped him go on a pilgrimage to Mecca?

A third member of the congregation said the FBI's informants were unreliable. He ridiculed its agents for warning his friend, a taxi driver who works 16 hours a day, that he was "moving around too much."

"Takbeer!" shouted the audience of about 80 people. "Takbeer!" The mosque official moderating the meeting quickly explained to the guests that the word "is a Muslim 'Hallelujah!' "

At some mosques, the angry questioning might have been considered imprudent. But not at Dar Al Hijrah, whose leaders have been outspoken in criticizing U.S. law enforcement actions against Muslims and U.S. policies in the Middle East.

Officials at Dar, one of the Washington area's oldest and largest mosques, know firsthand about U.S. government scrutiny. The FBI and the federal 9/11 commission concluded that two of the Sept. 11, 2001, hijackers briefly worshiped at the mosque after one of them befriended its imam in San Diego. FBI officials have said they found no evidence that the imam, who has since resigned and left the country, had prior knowledge of the attacks, and the commission's report said it was unable to reach a conclusion about his relationship with the hijackers.

Dar stands out among mosques in the Washington area for another reason. It is closely affiliated with the Muslim American Society, a 12-year-old organization committed to promoting Islam in the United States. Several of the group's founders had been active in the Muslim Brotherhood, a movement started in Egypt in the 1920s that advocates a purer, more restrictive form of Islam throughout the Middle East. Although the Brotherhood favors establishing Islamic law in predominantly Muslim countries, many of its members say they see no conflict between Islam and democracy.

Some U.S. government officials say the Muslim Brotherhood has dangerous links to terrorism, while others argue that most of the movement is moderate and should be enlisted as an ally against Islamic radicalism.

In many ways, Dar Al Hijrah illustrates the challenges of adapting a conservative, foreign-grown Islamic ideology to an American setting.

The mosque's leaders said their main focus, especially in the wake of the Sept. 11 attacks, is not Middle Eastern politics but community involvement that will serve to educate non-Muslims in this country about the Islamic faith and demonstrate that U.S. Muslims embrace American values.

"We are stepping up our civic participation and outreach efforts to make up for years of isolation that put us in vulnerable position: being a largely unknown community and therefore easy target of stereotyping," Souheil Ghannouchi, who is president of the Muslim American Society and serves on Dar's board of directors, wrote in a recent online chat. "Our main priority is to . . . develop viable models for American Muslim personality and for Islamic life in America."

The mosque, which opened in 1991, has pursued American Muslims' interests by holding candidate nights with Northern Virginia politicians, offering tours for schoolchildren, engaging in interfaith discussions and sponsoring voter registration drives.

But many younger Muslims have shied away from active involvement in the mosque's affairs, viewing its aging leadership as secretive and cliquish and objecting to its strict segregation of men and women. Although about 3,000 people attend Dar's three Friday prayer services -- perhaps the highest attendance for any mosque in the area -- its last internal election attracted only 120 voters.

Some members have begun to challenge the founders' attitudes. There is "no question" that the mosque leadership needs to be more open and inclusive of younger people, including women, said Esam Omeish, 36, a surgeon who lives in Alexandria and who is the youngest member of Dar's board. "The bottom line is that this is a mosque that is in the heart of Washington," he said. "Our goal is to make the congregation reflect that reality."

A Community of Immigrants

Hidden behind rows of tall evergreens on a street near Seven Corners, Dar has long been a magnet for recent Muslim immigrants. Hundreds of taxis, pickup trucks and economy sedans converge on the mosque on a typical Friday, and the worshipers are as likely to wear jeans and T-shirts, or the long smocks of their homelands, as business suits and ties.

"It's a diverse community" and "the place we meet our friends," said Falls Church resident Driss Lampkadem, 37, a Moroccan-born employee of Home Depot who stood outside the mosque on a recent Friday with his Moroccan friend, security guard Aziz Hilali, 31, of Alexandria.

About 60 percent of the worshipers are Arab, said mosque spokesman Johari Abdul-Malik, but an increasing percentage hail from such countries as Pakistan, Ethiopia, Bangladesh and Cambodia.

The roots of Dar Al Hijrah, which means "Land of Migration," lie in a group of mostly Arab college students who in the early 1980s broke from the Islamic Center in Northwest Washington, a mosque run by embassies of Muslim countries. After worshiping in temporary sites, the fledgling congregation purchased the 3.4-acre Falls Church property just off Route 7 in 1983. Three years later, it began construction of the $5 million mosque, with financial help from the Islamic Affairs Department of the Saudi Embassy in Washington. The mosque's current revenue comes entirely from the congregation, Omeish said.

Some Dar founders also were among the immigrant activists who started the Muslim American Society in 1992. Some had belonged to the Muslim Brotherhood in their native lands, where they often worked clandestinely against governments that had banned their movement. They faced an entirely different issue in the United States: how to retain their Islamic identity in a secular culture where they were a religious minority.

The founding of the society reflected the facts that their goals had changed and that they no longer needed to operate secretly, said Mohamad Adam El Sheikh, 58, a Brotherhood member in Sudan who helped launch both the American group and Dar, where he is the imam.

Those who founded the society felt that "we should cut relations with the [Brotherhood] abroad and regard ourselves as Americans. . . . We don't receive an order from any organization abroad, and [they] have no authority to tell us what to do," Sheikh said.

The society, based in Falls Church, now has 50 chapters across the country, many of them affiliated with mosques. Among its objectives, according to its Web site, are "to present the message of Islam to Muslims and non-Muslims," to promote understanding between the two groups and to encourage Muslims to build "a virtuous and moral society."

Society president Ghannouchi, the nephew of Rashid Ghannouchi, an Islamic scholar and activist known throughout the Middle East, is a native of Tunisia and has been in this country for almost 20 years. He declined several requests for an interview. Colleagues said he believes that Muslims in America should become active in their communities on local issues rather than be preoccupied with problems overseas.

"Even though we refuse . . . to be treated as a security problem and we are opposed to the way our government is conducting foreign policy, especially the way the war on terrorism is being conducted, we still enjoy many rights that Muslim activists do not enjoy in most Muslim countries," Ghannouchi wrote in the recent online chat that appeared on the society's Web site.

A Leading Role

The society is well-represented in Dar's leadership. Three mosque board members -- Ghannouchi, Omeish and Amin Ezziddine -- are active in the society, as is the mosque's administrative director, Samir Abo Issa. And the society's general secretary, Shaker El Sayed, is on the executive committee that runs the mosque's daily affairs.

The relationship between the society and Dar "is not a lockstep" one, mosque spokesman Abdul-Malik said. "But the work of MAS on the national level colors the work on the agenda of Dar Al Hijrah, definitely," he said. For example, "we had a voter registration drive because MAS is pushing a strong voter registration program."

But the prominent role of the society in Dar's internal affairs is controversial among Dar members. The mosque's constitution requires that four seats on the board of directors be assigned to top officials of national Islamic groups, including the society. Dar officials said the other five seats are reserved for mosque founders and prominent members.

This unelected board often meets behind closed doors, and it is unclear how many board members representing outside organizations actually attend. According to the mosque's Web site, Sayyid Syeed, secretary general of the Islamic Society of North America, is on the board. But in a telephone interview, Syeed said he resigned "at least five years ago."

The mosque's executive committee has seven members, four appointed by the board of directors and the other three elected by the mosque's general membership.

Omeish acknowledged that some mosque members "have some questions about the constitution . . . and this is an acceptable discussion." Specifically, he and others said, proposals under discussion include direct elections to the board, term limits and phasing out the seats assigned to officials of national organizations.

Those who have paid the mosque's annual membership fee of $50 for two years are allowed to vote in its elections. After only 120 people showed up for the April election to fill seats on the executive committee, an effort was launched to increase the mosque's membership, which has reached 250 families, Abdul-Malik said.

A Woman's Place

There are no women in these leadership positions. A few women ran for the executive committee in April, but none won a seat.

Women worship apart from men in an upstairs balcony and must enter the building through a separate rear door, and shaking hands with the opposite sex is discouraged.

Such treatment alienates some Muslim women. "One of the things that turned me off is that women's space is completely separate and you have to go in the back, right near the dumpster," said Saadia Yacoob, 23, a schoolteacher who lives in Sterling. "There is this general aura of 'We don't want you to be here.' "

Some female members also have complained about the attitude of mosque counselors, saying that victims of domestic abuse have been asked such questions as "Did you make a nice meal?" and "Have you been compliant enough?"

Some Muslims who find Dar too traditional instead attend the All Dulles Area Muslim Society in Sterling, a mosque that draws a Friday worship crowd of about 2,500 and has 800 registered members.

The board of directors at All Dulles is elected and has five women members, and its elected vice president is female. Women worship in the same prayer room as men, separated only by a two-foot-high lattice barrier.

Omeish said Dar needs to relax its gender segregation. "We're trying to combine" some activities now done separately, he added. But he noted that older and younger generations disagree on the role of women.

An Imam's Short Tenure

In early 2001, the mosque's leaders tried a different tack to increase its appeal to younger worshipers. They hired Anwar al-Aulaqi, then a resident of San Diego, as imam with a mandate to attract young people, especially non-Arabic speakers.

Born in New Mexico and raised in Yemen, Aulaqi was young, personable, fluent in English, conversant with Middle East politics and known for giving eloquent talks on Islam. "He was the magic bullet," mosque spokesman Abdul-Malik said. "He had everything all in a box."

Aulaqi's sermons did draw a lot of young people. But the charismatic preacher was on the job only about a year.

Shortly after the 2001 attacks, federal investigators learned that two of the hijackers, Hani Hanjour and Nawaf Al Hazmi, worshiped at Dar for several weeks in spring 2001. The two men apparently showed up because Hazmi had developed a close relationship with Aulaqi in San Diego, according to the report of the 9/11 commission.

Aulaqi later admitted to FBI agents that he had met Hazmi several times, but he claimed not to remember the specifics of their discussions and he denied having had any contact with Hazmi or Hanjour in Virginia, the report said.

Aulaqi returned to Yemen in March 2002, and the commission's report said he could not be located for an interview. Abdul-Malik said Aulaqi resigned from Dar because he felt that the post-9/11 news media attention was distracting him from his duties.

Omeish, one of the mosque officials who hired Aulaqi, said he is convinced that Aulaqi "has no inclination or active involvement in any events or circumstances that have to do with terrorism."

Mosque officials said sermons at Dar condemn terrorism. Sheikh, the current imam, said that suicide bombings are never legitimate in the United States, and Omeish agreed that "it's as clear as day that within the American context, it is absolutely contradictory to Islamic principles and belief."

But Palestinian suicide bombings in Israel elicit more ambivalent attitudes. Mosque spokesman Abdul-Malik said that he has condemned Palestinian suicide bombers in his own sermons and that no one criticized him for it afterward. But judging by conversations with members, the tactic generally is neither encouraged nor condemned from Dar's pulpit.

Sheikh said he tells his congregation that Islamic law does not allow suicide bombings in most instances. However, he said, "if certain Muslims are to be cornered where they cannot defend themselves, except through these kinds of means, and their local religious leaders issued fatwas to permit that, then it becomes acceptable as an exceptional rule, but should not be taken as a principle."

Omeish added that while there is "condemnation of indiscriminate killing of civilians" among mosque members, there is also "sympathy for the Palestinian cause. . . . It's a core issue in the community."

That sympathy extends to the Islamic Resistance Movement, or Hamas, which has been responsible for most suicide bombings in Israel and was designated a terrorist organization by the United States in 1995.

Last month, a former member of Dar's executive committee, Annandale resident Abelhaleem Hasan Abdelraziq Ashqar, 46, was indicted with two other men by a Chicago grand jury on racketeering conspiracy charges in connection with alleged efforts to raise money for Hamas beginning in 1988.

And a law enforcement document filed in federal court in Alexandria says Ashqar and two other longtime Dar members -- Mohamad al Hanooti, a former Dar imam, and Ismael Selim Elbarasse, a founding member of the mosque -- attended a 1993 meeting of senior Hamas leaders in Philadelphia.

Elbarasse was named as an unindicted co-conspirator in the Chicago case. He and Ashqar served time in jail for refusing to answer questions about Hamas before a grand jury that was probing the group before September 2001.

Talking Points

On a recent Friday, hundreds of men filled Dar's main prayer hall. Standing in the wooden minbar, or pulpit, mosque member Osama Abu Irshaid delivered a sermon.

He spoke of Iraq, where "almost 20,000 Iraqis and 1,000 Americans were killed" even though Iraq's leader "never had weapons of mass destruction." He mentioned recent Palestinian deaths and how "unfortunately, the administration of our country supports Israel." And he blasted the "discrimination" that American Muslims face.

Such problems, the 30-year-old Palestinian immigrant said, require Muslims to support each other. "It is a blessing," he added, "that we live in this country, where we can stand up for our rights."

The subjects of sermons -- two of which are given mostly in English and one in Arabic -- can be almost anything, Omeish said. "The key thing is . . . the principles of Islam must be respected at all times," he said. "And [the sermon] has to speak to the American context. We're American Muslims."

Since September 2001, he added, Dar's sermons have increasingly emphasized that it is no contradiction "to feel as patriotic Americans and as strong, faithful Muslims."

"We need to reach out and be part of the melting pot of America," he said. "If there is any concern . . . if anything is not clear, I want nothing less than you showing up at the doors of Dar Al Hijrah asking us those questions."

Staff researcher Margot Williams contributed to this report.

About 3,000 people pray at Dar Al Hijrah Islamic Center each Friday. Congregants are from around the world; about 60 percent are Arab.Because of height restrictions, the minaret at Dar Al Hijrah is set on the ground next to the building instead of atop it. Johari Abdul-Malik, the mosque's director of outreach, greets congregants after prayers. He said the mosque has made an effort to boost its formal membership, which stands at 250 families.Congregants greet each other after prayer. The mosque is "the place we meet our friends," Falls Church resident Driss Lampkadem said.Abelhaleem Hasan Abdelraziq Ashqar, a former Dar executive committee member, is charged with racketeering conspiracy in support of Hamas.