The documents, obtained by the American Civil Liberties Union under a Freedom of Information Act lawsuit, show, for instance, that military officials labeled as "potential terrorist activity" events like a "Stop the War Now" rally in Akron, Ohio, in March 2005.

The Defense Department acknowledged last year that its analysts had maintained records on war protests in an internal database past the 90 days its guidelines allowed, and even after it was determined there was no threat.

A department spokesman said Thursday that the "questionable data collection" had led to a tightening of military procedures to ensure that only information relevant to terrorism and other threats was collected. The spokesman, Maj. Patrick Ryder, said in response to the release of the documents that the department "views with great concern any potential violation" of the policy.

"There is nothing more important or integral to the effectiveness of the U.S. military than the trust and good will of the American people," Major Ryder said.

A document first disclosed last December by NBC News showed that the military had maintained a database, known as Talon, containing information about more than 1,500 "suspicious incidents" around the country in 2004 and 2005. Dozens of alerts on antiwar meetings and peaceful protests appear to have remained in the database even after analysts had decided that they posed no threat to military bases or personnel.

Some documents obtained by the A.C.L.U. referred to the potential for disruption to military recruiting and the threat posed to military personnel as a result.

An internal report produced in May 2005, for instance, discussed antiwar protests at the University of California, Santa Cruz, and was issued "to clarify why the Students for Peace and Justice represent a potential threat to D.O.D. personnel."

The memorandum noted that several hundred students had recently protested the presence of military recruiters at a career fair and demanded that they leave.

"The clear purpose of these civil disobedience actions was to disrupt the recruiting mission of the U.S. Army Recruiting Command by blocking the entrance to the recruiting station and causing the stations to shut down early," it said.

But the document also noted that "to date, no reported incidents have occurred at these protests."

The documents indicated that intelligence reports and tips about antiwar protests, including mundane details like the schedule for weekly planning meetings, were widely shared among analysts from the military, the Federal Bureau of Investigation and the Department of Homeland Security.

"There is simply no reason why the United States military should be monitoring the peaceful activities of American citizens who oppose U.S. war policies," said Ben Wizner, a lawyer for the A.C.L.U.

Joyce Miller, an official with the American Friends Service Committee, a Quaker group that learned that information on some of its antiwar protests was in the military database, said she found the operation to be a "chilling" and troubling trend.