PORTLAND, Ore. — The American Civil Liberties Union, Muslim and Arab groups and a mosque involved in a terrorist investigation have mounted a legal challenge to a provision of the USA Patriot Act.

The ACLU said the suit, filed yesterday in U.S. District Court in Detroit, is the first direct challenge to the provision of the act that lets FBI agents secretly order librarians and others to disclose reading lists or other information.

Librarians could not tell the patrons that the library had turned over records to the federal agency and would be legally bound to secrecy forever.

The provision, which allows the federal government wider latitude than in the past to seize records, books and papers in investigations of terrorism, could also apply to religious leaders, charity directors or doctors, the ACLU said.

“Our clients believe all of their records are at risk in these places,” said David Fidanque, director of the Oregon Chapter of the ACLU. “It’s unnecessary, dangerous and un-American.”

The groups that filed the suit are the Arab Community Center for Economic and Social Services, or ACCESS, in Dearborn, Mich.; the Muslim Community Association of Ann Arbor, Mich., which runs a mosque and school; the American-Arab Anti-Discrimination Committee, based in Washington, D.C.; the Council on American-Islamic Relations, also based in Washington; Bridge Refugee and Sponsorship Services in Knoxville, Tenn.; and the Islamic Center of Portland, an Oregon mosque also known as Masjed As-Saber.

“People who come to us, it is important they feel safe, their info is confidential, that we can be trusted by them,” ACCESS Executive Director Ismael Ahmed told The Detroit News. “That is difficult or impossible now.”

Muslim Community Association member Homam Albaroudi said FBI agents have visited his home.

He told the Detroit Free Press that he was afraid to join the suit because he feared government retaliation but did so “because I care about what’s happening to the country and to the Constitution.”

Albaroudi co-founded the Ypsilanti, Mich.-based Islamic Assembly of North America, target of a February FBI raid. Federal prosecutors say the group’s Internet sites promoted terrorism through suicide bombing and using airplanes as weapons.

The lawsuit targets section 215 in the anti-terror legislation, passed by Congress soon after the Sept. 11 attacks at the urging of the U.S. Justice Department. The ACLU said it names Attorney General John Ashcroft and FBI Director Robert Mueller as defendants.

The provision waives the usual requirement of probable cause if the investigation involves terrorism, and allows federal officials sweeping authority to search the records of people who are not suspected of any crime. The FBI must prove to a court that the records have bearing on an investigation.

The Justice Department has defended this provision of the act as a crucial weapon in the war on terrorism.

“The Patriot Act was a long overdue measure to close gaping holes in the government’s ability, responsibility and duty to collect vital intelligence information on criminal terrorists,” department officials said in a statement responding to the suit.

The lawsuit came on the same day as a Justice Department forum at Wayne State University on the Patriot Act featuring representatives from the U.S. attorney’s office in Detroit, the FBI and the Bureau of Immigration and Customs Enforcement.

“Some critics are creating a false choice between national security and civil liberties,” Detroit-based U.S. Attorney Jeffrey G. Collins said in a statement on the forum. “We want to explain to the public how we are applying the Patriot Act to protect both of these important interests.”

The lawsuit had been in the works for more than a year, said Fidanque, as the ACLU searched for a legal strategy to challenge the FBI’s new authority.

Secrecy, he said, has been a huge problem.

All the targets of domestic spying under the provision are unaware the government is gathering information about them from libraries, bookstores, churches or businesses they patronize. And, if the law stands, they will never know.

Even the number of orders issued under the provision is classified. The orders are granted by one court in the country — the Foreign Intelligence Surveillance Court that meets in the basement of the Justice Department building in Washington D.C.

“Ordinarily, courts require a concrete controversy and a concrete individual who has been affected by the government’s actions,” to hear a challenge to a law, said David Cole, a professor of constitutional law at Georgetown University.

In this case, there is no single individual challenging the government, just a number of organizations. But Cole said that courts have made exceptions in First Amendment cases where a general “chilling effect” of government action on a group of people can be proved, he said.

The ACLU contested the Patriot Act provision through members of Muslim civil and religious groups, claiming the members were likely targets and that that put a chilling effect on their freedom of expression, Fidanque said.

The Portland mosque, for example, had been at the center of an investigation into an alleged terrorism cell. Mosque President Alaa Abunijem said investigators have already used traditional subpoenas to gather mosque records on the suspects and their families.

Secret, so-called 215 orders “almost certainly” were part of the FBI’s probe into the mosque’s activities, said Ann Beelan, the ACLU’s lead attorney in the case.

Federal district Judge Denise Paige Hood in Detroit will hear the case.