The State Administration of Cultural Heritage does not support the excavation of the 1,300-year-old tomb of Wu Zetian, the only empress in Chinese history, a cultural official has said.

The administration official was responding to calls by some archaeologists that the Qianling mausoleum should be excavated.

Located 80 kilometers northwest of the ancient city of Xi'an, capital of the northwest's Shaanxi Province, Qianling is the joint tomb of Wu Zetian, who remained in power for 50 years, and her husband, Emperor Li Zhi of the Tang Dynasty (AD618-907).

It is the only tomb in China which contains the bodies of two emperors. Wu Zetian was buried in the tomb 22 years after her husband was interred.

Qianling is also the best preserved ancient tomb in China and has not been looted, said Liu Qingzhu, head of the Institute of Archaeology under the Chinese Academy of Social Sciences.

Discussions about the excavation of Qianling began many years ago, but applications to open the tomb have never been approved by the central government.

At a recent academic symposium, excavation of the tomb became a controversial topic again, with famous archaeologist Shi Xingbang, former director of the Shaanxi Archaeological Research Institute, strongly advocating that Qianling be explored.

He pointed out that certain fragile relics will rot underground as the years go by.

In the 1980s, Shi participated in the excavation of Famen Temple in Fufeng County, 118 kilometers from Xi'an. He found that all paper relics had rotted and that most of the silk relics were deteriorating.

He insisted that excavation of Qianling be started as soon as possible.

But other experts argue that China should hold off a bit, saying a plan has to be in place to protect the tomb's treasures before any digging begins.

"Many technical problems need to be settled to protect silk, wooden and paper relics," said Liu Qingzhu.

The cultural official said the Chinese government has stood firm on the principle of no active excavation of imperial tombs, and stressed the importance of protection and rescue in doing archaeological work.