Sections of an ancient Greek theater were discovered on Thursday during construction work in an Athens suburb, archaeologists said.

Until now, only two such buildings were known in the ancient city where western theater originated more than 2,500 years ago.

Fifteen rows of concentric stone seats have been located so far in the northwestern suburb of Menidi, according to Vivi Vassilopoulou, Greece's general director of antiquities.

"Another section appears to lie under a nearby road," she told The Associated Press.

"(The remains) were discovered during excavation work, supervised by archaeologists, for a new building," Vassilopoulou said. "But it is still very early to offer any conclusions."

The structure has not yet been dated, and further details are expected to emerge following a full excavation.

Menidi is thought to be built over the ancient village of Acharnae, the largest of a string of rural settlements outside ancient Athens. Ancient writers mention a theater at Acharnae, but no traces of it had been found until now.

The village was linked with Dionysos, the ancient god of theater and wine, as the Athenians believed that ivy -- his sacred plant -- first grew there.

Built in semicircular tiers on hillsides, ancient theaters were monumental, open-air structures that could seat thousands of spectators.

Theater first emerged as an art form in late 6th century B.C. Athens, where ancient playwrights competed for a prize during the annual festival of Dionysos -- in whose cult the art originated.

The works of Sophocles, Aeschylus, Euripides and Aristophanes were performed in the theater of Dionysos under the Acropolis.

Originally a terrace where spectators sat on the bare earth above a circular stage, it was rebuilt in stone during the 4th century B.C. and could sit up to 14,000 people.