Relics discovered at the Neolithic ruins at Taoyuan, a village in the city of Linfen, Shanxi province. [Photo by Zheng Yuan/Provided to China Daily]

Archaeologists have found ruins of a pentagonal structure believed to have been a tribal meeting hall or a leader's office from 6,000 years ago, authorities in North China's Shanxi province said Monday.

The semi-subterranean house, discovered at the Neolithic ruins at Taoyuan, a village in the city of Linfen, covered a total area of 90 square meters, with surviving walls reaching a maximum of 50 cm, said Xue Xinming, a researcher with Shanxi provincial institute of archaeology.

The walls were painted with a mixture of grass and mud inside, and several holes were also found where wooden pillars were located to support the house and walls, said Xue.

A cylinder-shaped fireplace was also found underground in the house, which ancient people used for heating, cooking and lighting.

According to Xue, the pentagonal building was rare for that period as the prehistoric people only built structures larger than 80 square meters in the shape.