Sen. Dianne Feinstein on Thursday asked for answers on an obscure Pentagon agency that included reports on student anti-war protests and other peaceful civilian demonstrations in a database meant to detect terrorist activities.

"Under what circumstances can peaceful protests at universities or by anti-war groups be monitored?" Feinstein, D-Calif., wrote in a letter to Defense Secretary Donald H. Rumsfeld.

"What authorities, and under what regulations, do military counterintelligence units have to conduct investigations on U.S. persons?" she wrote.

At issue is a classified database of information about suspicious people and activity inside the United States that's maintained by a three-year-old Pentagon agency called the Counterintelligence Field Activity, whose size and budget also are classified.

The database, which a Pentagon fact sheet says is meant to capture information "indicative of possible terrorist pre-attack activity," came to light a month ago when NBC News obtained details on its contents. The Pentagon acknowledged including information on anti-war activities and other meetings that should have been removed.

The Pentagon announced a review of the program, and Feinstein's office has been told that all inappropriate records have now been removed.

Among the reports until recently maintained in the database was one on an April protest at the University of California, Santa Cruz, by UCSC Students Against the War, Feinstein said Pentagon officials have confirmed to her staff.

Pentagon spokesman Cmdr. Greg Hicks said Thursday the review was ongoing. He said he had not seen Feinstein's letter but that Rumsfeld would respond to it after reviewing it.