Clay mausoleums dating back to the Western Xia Dynasty (1032-1227) in northwest China's Ningxia Hui Autonomous Region, Known as the "Pyramids of China", are in danger of collapsing due to damages by the elements, especially wind erosion, over the past 1,000 years.
"The largest tomb, about 15 meters high, has a two-m deep and one m-wide crack, and a 10-m stretch of the western wall has collapsed," said Dai Wenzhen, deputy director of the administration office of the tombs.
Most tombs belonging to noblemen face similar problems, Xia said, adding that partial ruin has been reported on some tombs.
"The whole group of noblemen tombs are in danger of vanishing," the official warned, calling for emergency measures to protect the cultural relics.
"Protection of the tombs must be put in place at once," Xia said.
The Western Xia Imperial Tombs comprise nine mausoleums of emperors and 207 tombs of noblemen.
In 2000, the Chinese government allocated 10 million yuan (about US$1.25 million) for the repair and protection of the No. 3 imperial tomb. Experts sprayed, daubed and injected chemical materials into the tomb walls.
The experts also reinforced the bottom of No. 1, 2, 4 and 6 imperial tombs to curb the wind erosion.
As a result of these substantial, effective efforts, the collapse of some of the imperial tombs has been slowed. But other noblemen tombs have not received adequate protective measures owing to the lack of financial support.
The Western Xia mausoleums, together with 13 other natural attractions and cultural relics, have been list in the first group of the country's heritage list.