BEIJING - Jokhang Temple in southwest China's Tibet autonomous region will repair and reinforce an ancient monument marking the historic alliance between Tibet and the Tang Dynasty (618-907), a senior Tibetan official said Sunday.

The Tang-Tubo Alliance Monument, which is now enclosed by walls in front of the temple, will open to the public but needs protection work due to its long-term exposure to air, said Jigmyi Namgya, vice mayor of Lhasa, the regional capital of Tibet.

The 3.42-meter monument was erected in 823 AD in Lhasa. Its inscription, carved in both Tibetan and Chinese characters, eulogized the alliance between the central government of the Tang Dynasty and the Tubo Kingdom that ruled the Tibetan Plateau from the 7th to 9th centuries.

Jigmyi Namgya said the monument witnessed the great unity between the two sides at that time. Emperors of the Tang Dynasty married two princesses to Tibet, who were highly esteemed by the Tibetan people.

China has invested heavily in preserving heritage sites in the Tibetan region, planning to spend 200 million ($31.8 million) repairing Lhasa's 56 ancient buildings from 2011 to 2015, said Jigmyi Namgya.