The New York Civil Liberties Union on Monday sued to stop the NYPD's program of surveillance of Muslim groups and neighborhoods, alleging it violates a 1985 court decree limiting police intelligence gathering.

According to news reports cited in the Manhattan federal court lawsuit, the NYPD infiltrated mosques and student associations, looking for extremist tendencies and keeping files on people deemed suspicious.

The so-called "Handschu" decree, issued in response to police domestic intelligence gathering on political groups during the 1960s and 1970s, bars investigation or spying on people when there is no indication of links to terrorism or other unlawful activity.

"Investigations of any community which are not based upon indications of crime create fear and erode the confidence of a community in the power of a legal system to protect it," said NYU law professor Paul Chevigny, one of the lawyers who filed the suit.

The NYPD, in response to the lawsuit, referenced the memory of Sept. 11 and subsequent efforts on more than a dozen occasions to launch terror attacks against the city.

"The NYPD adheres to the Constitution in all it does, and specifically the Handschu guidelines in the deployment of undercover officers to help thwart plots against New York City and to identify individuals engaged in support of terrorism," spokesman Paul Browne said.

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