US Ambassador Terry Branstad's visit is taking place amid escalating trade war between US, China (File)

China, which granted a rare permit for US Ambassador Terry Branstad to visit Tibet, on Monday hoped that the American envoy would make an "unbiased judgement" about the conditions in the Himalayan region especially on religion and the Tibetan culture.

Branstad was travelling to China's Qinhai province and the bordering Tibet Autonomous Region from May 19 to May 25, making the first trip by an American envoy to the highly restricted area in four years.

During his visit, Branstad is due to have meetings with local officials and visit religious and cultural heritage sites.

His visit is taking place amid escalating trade war between the world's two largest economies.

China's permission to him came after US early this year passed Reciprocal Access to Tibet Act of 2018 warning equal and reciprocal measures if Beijing denied access to American citizens, government officials and journalists to Tibet, the homeland of the exiled Tibetan spiritual leader, the Dalai Lama.

The new law would impose a visa ban on Chinese officials who deny American citizens, government officials and journalists access to Tibet.

Currently, foreign tourists need a special travel permit to visit Tibet in addition to a Chinese visa.

Asked why China, which denied permission for US Ambassador to visit Tibet last year decided to do so now, Foreign Ministry spokesman Lu Kang told the media on Monday that "we welcome Ambassador Branstad's visit so that he can see the major changes which took place in Tibet for past 60 years after the peaceful liberation."

Commenting on US embassy's statement that the visit is a chance for the ambassador to engage with local leaders to raise longstanding concerns about restrictions on religious freedom and the preservation of Tibetan culture and language, Lu said China hopes the envoy could make unbiased judgement on the prevailing situation in Tibet.

"As for the comments from US embassy, we hope this visit can help them make unbiased judgement that is fact based especially on the religion, culture, heritage and history. We hope he can make his own judgement instead of being misguided by rumours," Lu said.

"We welcome all those who have an objective view of China's economic and social development, including Tibet to this region. His request was denied (last year), I don't know what you mean by that. All the diplomatic personnel in China if they have this need to visit the regions in China, they need to apply to relevant authorities first," he said.

In March, China issued a white paper defending its policies and highlighting major economic development and improvement of lives of people in the remote Himalayan region since a failed uprising against Beijing's rule 60 years ago.

About 150 Tibetans committed self-immolations in different parts of Tibet since 2009 calling for the return of 83-year-old Dalai Lama from his exile and improvement of human rights in the Himalayan region.

The Dalai Lama, the spiritual leader of Tibet, crossed the border into India following a failed uprising against Chinese rule in Tibet on March 31, 1959.

China says Tibet for centuries has been its territory well before People's Liberation Army (PLA) took control of it in 1950.