In the wake of the terrorist attacks on the United States, there are many reports of harassment of Muslims in America, even of Sikhs who are mistaken for Muslims. Many Muslim stores have shut down and Muslim students have stayed away from classes.

At a press briefing in Washington, leaders of prominent Muslim organizations described some of their problems while strongly condemning the attacks. There is no religious or political justification or any kind of justification for the terrorist attacks on the United States, said Shaker El-Sayed, secretary general of the Muslim American Society:

"Our stand is absolutely clear on this issue," he said. "We cannot accept cowards' attacks on civilians. We will never support them, justify them, condone them or even explain them. We join all other Americans in our unequivocal condemnation of the attacks as un-Islamic, barbaric and inhumane. We also want to point out that retaliation against the perpetrators, their accomplices and the network of their associates is a must, if we are to protect against future possible similar incidents."

At a press briefing held by leaders of Muslims organizations, Mr. El-Sayed noted that American Muslims, like other Americans, have vigorously responded to the crisis. They have started blood drives, volunteered for other services and offered information to law enforcement agencies.

But some Americans have a different image of Muslims, said Raeed Tayeh of the United Association for Studies and Research. After the attack, he said Muslims have been targeted for abuse and sometimes physical harm:

"The media has failed to show that there is really a national epidemic," he said. "Yesterday I was speaking to the imam of a mosque in Cleveland, and a person had driven a car into the mosque through the foyer, damaging the property severely. It is as if people are mimicking the terrorist attack by taking their cars and slamming them into buildings, whereas the terrorists took planes and slammed them in."

Some of the speakers at the briefing were especially critical of the FBI for what they consider to be overly aggressive tactics. Stanley Cohen, an attorney who is representing Muslims, complained that FBI agents have gone into mosques during worship services and shown slides of suspects.

Mr. Cohen said if they were refused entrance, they waited outside and took down license plate numbers in an intimidating fashion. "There is a war at home that is beginning now, and I find it interesting that at the very moment the elected officials in this country are attempting to douse the flames of repression, racism and prejudice, gasoline is being poured on those flames by the Federal Bureau of Investigation."

An unprecedented attack requires some speedy, perhaps intrusive measures, says Larry Johnson, a longtime analyst of terrorism. Since Muslims were involved in the attacks, the FBI is going to have to talk to Muslims, even perfectly innocent ones, to try to get information.

"To the extent that someone's civil liberties are violated and that can be proven later, then there are ways to redress that," he said. "But there has been an extraordinary emphasis by both the President and the attorney general that this is not designed to target Muslims, not designed to target Arab Americans, but is designed to go as quickly as possible to find those responsible for these terrible attacks.

Mr. Johnson adds that the terrorist network is so complex and far reaching that many avenues have to be pursued. "It may very well be that the folks are moving the money through charitable organizations or through some mosques," he said. "It's possible. It is equally possible that those who are lending their cooperation are doing so unwittingly. If there was a terrorist attack that appeared to be involved with the IRA, I would fully expect the FBI to go into a Catholic church if the evidence led in that direction."

Mr. Johnson says a solution to this grave crisis will come as a relief to Muslims as well as to other Americans.