Xinjiang territory profile
China's largest province Xinjiang is bordered by eight countries including the former Soviet Central Asian republics, Mongolia, Afghanistan, Pakistan and India.
The region experienced a brief period of independence in the 1940s but China regained control after the Communists took power in 1949.
It is home to the Turkic-speaking Muslim Uighur minority who make up about 8 million of the province's 19 million people.
Rich in natural resources, economic development in the region has been accompanied by large-scale immigration of Han Chinese.
Many Uighurs complain of discrimination and marginalisation by the Chinese authorities. Anti-Han and separatist sentiment has become more prevalent since the 1990s, flaring into violence on occasion.
In 2018 rights groups and the US State Department accused China of increasing its crackdown on the region with the aid of surveillance technology and of detaining "at least" tens of thousands of people in re-education camps.
One group, China Human Rights Defenders, said government data showed nearly 228,000 people had been arrested in 2017, nearly a fifth of all arrests in China, even though the region has only 1.5 percent of the country's overall population.
China's government has not commented on the issue but Chinese media have defended the measures as necessary to combat religious extremism.
Several hundred Uighurs are reported to have fought for the Islamic State group in Syria and Iraq and returning fighters could well pose a security threat.
Xinjiang's media are tightly controlled by the local Communist Party and government. The Urumqi People's Broadcasting Station and the Xinjiang People's Broadcasting Station run radio and television broadcasts in Chinese, Uighur and minority languages.
Major state-run newspapers include the Chinese-language Xinjiang Economic Daily.
The authorities imposed a months-long shutdown of internet access in Xinjiang following the violent unrest in July 2009. Bloggers, netizens and website managers were "singled out for repression", Reporters Without Borders said.
In July 2017 authorities demanded that residents install an application on their mobile phones that scans the devices and reports back to authorities on what it finds.