Building work started Saturday to expand Tibet Museum in Lhasa, capital of Southwest China's Tibet autonomous region.

The project is set to be completed in 2020 and will expand the 23,000 square-meter building to 58,000 square meters at a cost of 660 million yuan (about 100 million US dollars).

The building will maintain a traditional Tibetan style, and will use solar energy, taking advantage of the city's abundant sunlight, according to Liu Yi, one of the museum designers.

After completion, the museum will be able to accomodate 7,000 visitors a day, according to the region's cultural relics bureau.

The museum has been closed since December 2016 to prepare for the expansion. During the construction, the museum will organize exhibition tours in the region.

Tibet Museum opened in 1999 and is one of the largest in Tibet.

It has more than 520,000 artifacts, including pottery, jade, and Buddha statues, attracting hundreds of thousands of visitors every year.