LOS ANGELES - The American Civil Liberties Union (ACLU) of Southern California and the Council on American- Islamic Relations have filed a lawsuit against FBI for violating the First Amendment rights of Moslems, court papers showed Wednesday.

The FBI paid an informant to report on activities at several mosques in violation of the First Amendment, according to court papers obtained on Wednesday.

Related readings:  FBI: Same gun shot at Pentagon, Marines' museum  FBI says cyber-thieves stole $70 million  Pentagon says not negotiating with Wikileaks  US couple had 20 names on hit list

The lawsuit was filed in US District Court in Los Angeles Tuesday on behalf of three Moslems, sources with the ACLU said.

The plaintiffs, who want the lawsuit certified as a class action, seeks damages and the destruction of all materials collected by a former FBI informant.

The lawsuit alleges that ex-FBI informant Craig Monteilh violated the constitutional rights of Moslems by  infiltrating mosques and recording conversations in a search for potential terrorists.

The FBI's action was based solely on religious grounds, according to the lawsuit.

The plaintiffs contend that over 14 months, beginning in 2006, the FBI used Monteilh to "indiscriminately" collect personal information on hundreds or even thousands of Muslim Americans.

Monteilh, who has served time in prison for forgery, claims he was recruited by the FBI in 2004 to infiltrate drug-trafficking groups, according to the lawsuit.

In 2006, he said, he was asked to assume the identity of a Moslem convert and go undercover to identify extremists and gather intelligence.

But the FBI defended its action. FBI spokeswoman Laura Eimiller said the agency investigates allegations of crimes, "not Constitutionally-protected activities, including the exercise of religious freedom."

Eimiller said the FBI does not investigate houses of worship or religious groups, "but individuals who are alleged to be a threat to national security or involved in criminal activity."

ACLU lawyer Peter Bibring dismissed the idea that the FBI may have been targeting individuals already suspected of criminal activity.

"That simply doesn't fit with the behavior that the entire community observed," he said. Monteilh "didn't focus on individuals or small groups of people. He probed a wide range of people."