XINING -- Chinese experts have restored a 700-year-old handwritten copy of the Quran, the sacred book of Islam, in northwest China's Qinghai Province.

Related readings: Egypt condemns guards for Quran incidents White House plays down new Quran reports US confirms Gitmo soldier kicked Quran Newsweek urged to do more to repair damage Newsweek retracts story on Quran abuse

The 867-page, two-volume set, the oldest known in China, is written in Arabic and stored in the Jiezi mosque in Xunhua County. The restoration work was done by experts from the Nanjing Museum.

The Quran was brought to China when the Salar ethnic group moved east from Maracanda, the ancient name of Samarkand in Uzbekistan, about 700 years ago. Experts believe it was written between the eighth and the 13th century.

"This copy was handwritten by Arabian Muslims, while other ancient copies in China where written by Chinese Muslim," said Ma Weimin, deputy director of the Qinghai Provincial Cultural Heritage Bureau, adding that the copy is a valuable research tool for the study of the origin and history of the Salar ethnic group.

The books had to be repaired and restored as they had seriously deteriorated and were in danger of rotting, said Ma.

Xi Sancai, director of the cultural relics preservation technique research institute with the Nanjing Museum in east China's Jiangsu Province, and his colleagues undertook the restoration job.

The restoration began with a scientific analysis of the paper and ink,cleaning and removing mildew, and mended damaged pages by using the most advanced technologies.

The restored Quran will be preserved in a special box where the temperature and humidity are fixed and ultraviolet rays and harmful gas are kept out.