The US ambassador to China is making the first trip to Tibet by an American envoy in four years after obtaining rare access to the restricted region, his embassy said yesterday.

The visit by Ambassador Terry Branstad comes two months after the US State Department said Beijing had "systematically" impeded access to Tibetan areas for US diplomats, journalists and tourists.

Branstad was scheduled to visit Qinghai province and the neighbouring Tibet Autonomous Region from Sunday until this Saturday, an embassy spokesperson said in an email to AFP.