LHASA, April 5 (Xinhua) -- Archaeologists have found 13 tombs, which are estimated to be between 1,800 and 2,700 years old, in Bomi County of southwest China's Tibet Autonomous Region.

The tombs were discovered by construction workers during a road project in Qundo township, Nyingchi, in the second half of 2016, according to the regional institute of cultural relics.

Two relatively complete human skeletons were found in two tombs, while human bones were also discovered in other graves, said Shaka Wangdu, associate researcher with the institute.

Archaeologists found that the tombs appeared to follow a known burial custom, which is still seen in parts of Qundo. According to the custom, after the body has decayed, the bones are exhumed and reburied.

Objects including eight complete examples of pottery, a millstone, three bronze arrowheads and iron residue were also found.

"The tombs will help research into Tibetan funeral customs and human development in eastern Tibet in a period without written records," said Shaka Wangdu.