Archaeologists have discovered a cluster of over 260 ancient tombs in the city of Sanmenxia, in central China's Henan Province, local authorities announced on Thursday. 

Along with these ancient tombs, the excavations revealed a large number of burial objects, including ancient bronze chimes that have not been found in the area for several decades. Nearly 100 of the tombs have been excavated so far, all of which are rectangular in shape. 

"These tombs from the Warring States Period (475-221 B.C.) were arranged in an orderly way. They might belong to a planned cemetery," said Yan Fei from Sanmenxia's institute of cultural relics and archaeology, who is leading the excavation project. 

Archaeologists discovered the tomb cluster while coordinating with the construction of a local project in the city, said Yan.

A large number of burial items, such as bronzeware, jade articles, agate accessories, bronze weapons and bone objects, have been unearthed at the site. 

A total of nine bronze chimes and 10 stone chimes were also excavated. This is the first time since the city of Sanmenxia was founded in 1986 that bronze chimes from the Warring States Period have been discovered, Yan added. 

"The discovery of these ancient tombs will provide valuable information for the study of the historical and cultural features of the western Henan in pre-Qin period (pre-221 B.C.), the livelihoods of the people at that time and the layout of cemeteries in the early Warring States Period," said Zheng Lichao, head of the Sanmenxia institute. 

Excavation and research work is still in progress.