The ACLU and Muslim advocacy groups are suing the FBI for allegedly failing to turn over records that would detail suspected surveillance activities outside mosques and other community centers.
The lawsuit was filed Monday in U.S. District Court in Santa Ana.
It alleges the FBI has only turned over four pages of documents to a coalition of Muslim groups even though they filed a joint Freedom of Information Act request more than a year ago.
The request asks for all records detailing surveillance and investigations of mosques and their organizations since January 2001.
A spokeswoman for the FBI did not immediately return a call for comment.