Archaeologists have recently excavated 31 tombs dating back to the Han Dynasty (206 BC-220 AD) in north China's Inner Mongolia Autonomous Region, according to the local cultural relics and archaeology institute.

The tombs are located in an ancient city of the Ming Dynasty (1368-1644), where items of the Han Dynasty were previously discovered nearby. Experts of the institute preliminarily concluded that there may be a city of the Han Dynasty under the city of the Ming Dynasty.

Archaeologists said that of the 31 tombs there were many different types, and more than 200 burial items including pottery, bronzeware, ironware, stoneware, woodware and shells were unearthed from the tombs.

"Pottery unearthed in the tombs is considerable in quantity, diverse and well-preserved, which fully reflects the burial customs in this area at that time," said Li Zhen, an expert with the School of History and Culture, Inner Mongolia Normal University.