Unable to sleep, Muqtedar Khan got up at 3 a.m. and went to his computer. Within an hour, the Michigan-based political scientist had posted "A Memo to American Muslims" on his Web site.

The Indian-born Khan said his fellow Muslims were "practicing hypocrisy on a grand scale" by protesting Israeli treatment of Palestinians but ignoring far worse human rights abuses by Muslim governments. And he criticized Muslims who "love to live in the U.S. but also love to hate it."

"It is time that we acknowledge that the freedoms we enjoy in the U.S. are more desirable to us than superficial solidarity with the Muslim World. If you disagree, then prove it by packing your bags and going to whichever Muslim country you identify with," wrote Khan, 35, who teaches at Adrian College.

"It is our responsibility to prevent people from abusing Islam," he continued. "We should have made sure that . . . Sept. 11th should never have happened."

The Oct. 5 memo has generated more than 230,000 hits to Khan's Web site. Many Muslims responded favorably, but many others did not. A colleague of Khan said he had overreacted, and a childhood friend told him he had "sold out to America."

As that incident illustrates, the events of Sept. 11 have sparked a vigorous debate among American Muslims about the competing demands of religious solidarity and national identity.

Like Khan, some are calling for critical soul-searching. They are urging American Muslims to tone down their anti-U.S. rhetoric, denounce all forms of oppression and terrorism -- even if that means criticizing other Muslims -- and begin to work more openly for the interests of their country.

Awais Sufi, a 28-year-old corporate lawyer in the District, said such ideas are "harsh medicine, but it's medicine that needs to be ingested by our community." Sufi, who is of Pakistani descent, called the attacks on the World Trade Center and Pentagon "a turning point" and said that "the way we react . . . is going to shape our identity for many years to come if not forever. We need to assure the American population . . . that we are an integral part of the fabric of the country and are able to contribute to its well-being."

Such sentiments led to the creation of Muslims Against Terrorism USA, a coalition of young professionals who, according to the group's Web site, are "sick and tired of extremists dictating the public face of Islam."

Other U.S. Muslims have called for their community to take a more active role in tracking down theaccomplices of the Sept. 11 hijackers. Some also want U.S. mosques to reassess the common practice of going overseas to hire prayer leaders, saying that these foreign imams have a political and social outlook that is out of sync with American realities.

But some Muslims fear that too much public self-criticism will divide their community, play into the hands of those they call "Muslim bashers" and weaken their efforts to influence U.S. foreign policy, especially on the Israeli-Palestinian conflict. Those fears were evident in some of the reactions to Khan's memo.

"This is not something you do, taking your voice to the public which is uninformed. And our enemies are waiting for something like this to happen," said Howard University graduate student Altaf Husain, 31, who is national president of the Muslim Student Association. "You will not find anybody that agrees with 90 percent of what [Khan] says. . . . He's not addressing American Muslims."

Some took exception to the sweeping nature of Khan's criticism. "It seemed like he was assigning culpability to all American Muslims," said Arsalan T. Iftikhar, 24, a student at the Washington University School of Law in St. Louis.

Underlying the debate are longstanding tensions between a younger, American-born generation of Muslims and an older, mainly immigrant leadership. Those promoting self-criticism in the community tend to come from the younger generation.

Tensions also arise from the ethnic diversity of America's Muslims. About 35 percent are of South Asian descent, 25 percent of Arab origin and 30 percent African American, with the rest coming from a variety of countries. Although all Muslims feel they have a stake in the future of Jerusalem, considered one of their holy cities, those of Arab descent are the most passionate about the Israeli-Palestinian conflict.

Many of those calling for more self-policing in their community have focused on the power of language, saying U.S. Muslims should stop tolerating inflammatory speeches that cast the United States as an evil empire.

"Since September 11, people have to basically choose between whether we're going to keep the old rhetoric -- that as Muslims we have to be united at any cost and support any Muslim anywhere -- or whether we have to identify what is right and what is wrong," said Radwan Masmoudi, executive director of the Center for the Study of Islam & Democracy, a Washington-based think tank.

"In the past, Muslims tended to always blame the others, whether it's the United States or Israel," he said. "Obviously, it has to stop."

Faizul Khan, imam of the Muslim Community Center in Silver Spring, laid down a marker recently, denouncing the extremism of Osama bin Laden and telling his congregants that "if you subscribe to this kind of belief, we don't want you here."

He said in an interview that although he believes his congregation "is vehemently opposed" to bin Laden, he thought it was important to make his own position absolutely clear.

In a recent article for Pacific News Service, Hasan Zillur Rahim deplored the lack of such condemnation of bin Laden by U.S. Muslim clerics in 1998, when the Saudi-born fugitive issued his appeal to Muslims to kill Americans everywhere.

Rahim, a Bangladesh-born Muslim who is a software consultant in San Jose, Calif., also criticized the practice of hiring foreigners to serve as imams at U.S. mosques -- hired because they speak the language of the mosque's immigrant congregation or because the mosque is receiving financial support from a foreign country.

Imad-ad-Dean Ahmad, president of the Bethesda-based Minaret of Freedom Institute, another Islamic think tank, said he would like to see Muslims "find practical ways to help identify" those responsible for the Sept. 11 attacks. In a forthcoming article for an Islamic journal, Ahmad advocates forming "an international commission of widely respected Muslims" that anyone with information about terrorists could go to.

"I'm talking about Muslims throughout the world doing what the Koran commands them to do, which is stand for justice," said Ahmad, who is of Palestinian descent.

Muslims Against Terrorism USA aims to educate Muslims and non-Muslims alike aboutIslam's prohibitions on violence against innocents. So far, the group has signed up 130 volunteers nationwide to visit churches, schools and civic groups, said its spokeswoman, Aasma A. Khan.

Sufi and his wife, Tammy, who live in Arlington, were among the coalition's founders. He is writing grant applications to foundations while his wife serves as national volunteer coordinator.

"We felt there is a need for a consistent, articulate and credible message that the religion of Islam is not about what happened on September 11," Sufi said.

Still, Muslims who publicly criticize their community are often censured. Rahim said he drew heat for his article. And Egyptian-born Khaled Abou El Fadl, a professor of Islamic law at the University of California at Los Angeles, recounted that after "speaking critically but responsibly" about his community in remarks at Harvard University, a colleague suggested Fadl had been too harsh. "His comment to me," Fadl said, "was, 'Take a Prozac.' "

In a sign of how sensitive Khan's "Memo to American Muslims" was, the Washington-based Council on American-Islamic Relations -- one of the country's highest-profile Muslim advocacy groups -- was reluctant to discuss it. A council spokesman would say only that Khan is "free to publish whatever he likes."

"Any time you stand up and criticize the Muslims or ourselves, you are seen as a traitor or a sellout," Masmoudi said. "That's what people are criticizing Muqtedar Khan for. They're asking, 'Why is he not criticizing U.S. foreign policy?' "