Twelve Marine guards at the president's Camp David retreat have been relieved of their duties because investigators believe they have been smoking marijuana, a Marine Corps commander said yesterday.

The 12 men were transferred Friday from the camp in the mountains of western Maryland to the Marine barracks in Southeast Washington, said Col. John Monahan, commander of the Washington barracks, as part of a wide-ranging investigation into marijuana use by marines in the Washington area.

Last weekend, Monahan said, two enlisted men were caught smoking marijuana inside the Marine barracks. Later in the week, he said, two others were caught, and questioning these suspects led to the "bust" at Camp Cavid.

None of the men is accused of smoking while on duty, Monahan said, but it is against military regulations to use drugs anywhere. He sais they are suspected of smoking pot at their homes near Thurmont, Md., where the presidential retreat is located.

On Friday a substance believed to be marijana was confiscated inside a car belonging to a marine at the Washington barracks, Monahan said.

Another officer said hub caps were taken off all cars at the barracks as part of the search and that more marijuana was found in a bedroom at the barracks hidden beneath a poster.

"It's really getting tight around here," one marine at the barracks told a reporter yesterday. "The officers are really cracking down on (marijuana smoking). They say they're going to bring out the dogs to sniff around, but that hasn't happened yet."

Monahan said the investigation is being conducted by the Naval Investigative Service. So far, he said, none of the suspects has been arrested or confined, but he been arrested or confined, but he said they may face charges at a court-martial.

In 1973, Camp David guards were transferred to other assignments because an investigation uncovered marijuana use among them.

There are 851 marines attached to Washington barracks, he said, including the contingent at Camp David and members of the Marine Band.