An activist group claims FBI documents show the government spied on it because of its anti-war views, but the FBI said the surveillance was part of a criminal investigation of one specific person, not the group.

The Thomas Merton Center, an interfaith activist group that cites peace and social justice as its objectives, on Tuesday released 11 pages of FBI documents obtained by the American Civil Liberties Union under the Freedom of Information Act.

The documents show the government targeted the Merton Center because of its views when some members conducted anti-war leafleting in Pittsburgh in November 2002, said Mary Catherine Roper, the ACLU attorney who filed the request.

But Agent Bill Crowley, spokesman for the FBI's Pittsburgh office, said the group wasn't being investigated, although an individual thought to be associated with it at that time was.

"We don't investigate groups. We investigate individuals," Crowley said.

The ACLU has accused the FBI of misusing terrorism investigators to monitor domestic political organizations, including several anti-war groups. The FBI has denied singling out individuals or groups based solely on activities protected by the Constitution's guarantees of free speech.

Roper said Tuesday the ACLU and Merton Center aren't claiming the FBI surveillance in Pittsburgh was illegal.

"This isn't about legal recourse. It's not about suing the government," Roper said. "What this is about is exposing the practices of the government so that the people can speak out about whether they want their government to be doing this."

The FBI documents show that investigators spoke with at least one unidentified source to gather information about the Merton Center. Those four pages are heavily redacted and don't show what information was shared with investigators.

Crowley acknowledged that an agent took photos of someone passing out anti-war leaflets on November 29, 2002, but he said the photos were only used to compare with photos of a person under FBI investigation.

"Once that comparison was made, and determined to be of no value to the ongoing investigation, the photos taken at the event were destroyed," Crowley said in a statement.