LHASA, April 18 (Xinhua) -- More than 1.1 million folios of 3,281 ancient books and documents have been archived over the past three years at the Potala Palace in southwest China's Tibet Autonomous Region.

The progress was announced at a relics protection conference in the region, following completion of the first phase of a 10-year project that began in late 2018. It aims to protect ancient texts at the palace, with a total investment worth 300 million yuan (about 47 million U.S. dollars).

The Potala Palace, located in the regional capital of Lhasa, was built by Tibetan King Songtsen Gampo in the seventh century and expanded in the 17th century.

The Palace was included on the UNESCO World Heritage List in 1994 and holds a collection of invaluable scriptures, historical documents, and precious relics, including statues, paintings and frescoes.

The Palace collection includes tens of thousands of ancient books and documents in Chinese, Tibetan, Manchu, Mongolian and Sanskrit.