The Nazi officer -- a slender, elegant figure -- enters from Pennsylvania Avenue, playing reveille on his trumpet. He is accompanied by three burly secret police types in heavy overcoats -- they are Bulgarians, Germany's allies in World War II, and the occupiers in the town of Skopje, Yugoslavia.

The action suddenly switches to the fountain at the intersection of Indiana Avenue, 7th Street and C Street, and the audience turns around: a bunch of revelers sing in Romany, "How happy is the Gypsy."

That is how the play "The Liberation of Skopje" begins. What follows is a series of masterfully crafted parables of brutality -- remembrances of a war that is still not over in that part of the world.

The Nazi officer and his men start shouting. The action is intense, threatening. The audience, caught between the two hostile groups, draws back and clears the space. A reveler is beaten and dragged away.

But "The Liberation of Skopje" is not street theater or a happening, 1970s style. Dusan Jovanovic's play is a tightly structured, forcefully acted drama of wartime, and it is closer to a medieval morality play than to contemporary avant-garde theater. The troupe, the Zagreb Theatre Company, is an independent company, an oddity in Yugoslavia where the state subsidizes up a hundred theaters. The play was originally performed in intimate baroque courtyards, but it loses nothing of its power in downtown Washington, where the audience first stands and then moves to bleachers.

From the moment the Nazi officer appears, the war that ravaged an obscure Balkan town 40 years ago becomes as grubbily real as the asphalt. There is not a word of English -- the play is in Serbo-Croatian, German and Romany -- but the images tell the story: The guiltridden blond who sleeps with the Nazi to secure the release of her brother, a resistance leader. The resistance leader who is crippled by torture and is suspected of betraying his comrades. The Jewish girl who plays melancholy tunes on the piano. The children whose favorite game is "firing squad." The grandmother whose leg is amputated and who begs for a chocolate. One Gypsy who gets shot by the Bulgarian secret police and the other who arranges to get himself shot because he betrayed a comrade. And the guerrilla leader who returns after victory to put everything in order.

An English-language synopsis is handed out by Source Theatre Company, Washington sponsors of the troupe. It makes clear that much of the play reflects a child's yearning for his guerrilla father, who is away in the mountains. The children shout from the rooftop: They knew only the indignities of occupation while their fathers fought a glorious guerrilla war; they will never understand each other. And throughout the play one hears the haunting refrain of the word svoboda -- freedom -- which everyone speaks but nobody understands. THE LIBERATION OF SKOPJE -- At 7th and Pennsylvania nightly through August 28 (dark on the 24th). Tickets $10; call 462-1073.