FT. DEVENS--Eighteen people were detained and then released here yesterday morning after distributing an estimated 200 copies of the Pentagon Papers to G.I.'s at the Ft. Devens Army Base.

The 18 were apprehended at six different locations around the 10,000 man base. No formal charges were filed by the Army, but the base commander banned five of the demonstrators from re-entering the base and all those arrested were photographed and fingerprinted before being released.

In addition, two reporters from a Boston radio station were arrested, then photographed and fingerprinted. An Army public information officer, Capt. Richard Ortwein, returned the photographs and fingerprints when he discovered they were newsmen.

Yesterday's action was organized by the Ayer, Mass. Common Sense Bookstore Collective and a group of G.I.'s from the base here. A total of 23 persons participated in the distribution of the paperback edition of the Pentagon's massive study of U.S. involvement in Vietnam. Leaflets containing excerpts from the study were also handed out.

Four of the demonstrators arrested yesterday received letters from acting base commander Col. Nicholas D. Rudziac forbidding their return to the Ft. Deven facility. A fifth received a similar missive later in the day from an officer on duty.

The entire group of 23 had entered the base at about 10:45 a.m. and started distributing their materials at six locations before being apprehended. Twelve from the original group returned to the base in the afternoon to try to talk to G.I.'s about the morning's action, but they were asked to leave.

Ft. Devens is an open base and no pass is required to enter the grounds. The base is an Army security post where men are trained for work in Army, Navy and Air Force security operations. It is also a staging area for men assigned to overseas duty, including combat duty in Vietnam.

The distribution of the Pentagon Papers centered at the main post exchange, the Army Security Agency