(Bloomberg) -- China may be holding as many as one million members of its Uighur minority in “re-education” camps in its western region of Xinjiang, according to United Nations human rights experts.

Speaking in Geneva on Aug. 10 during the opening session of a two-day review into China’s policies, Gay McDougall, a member of the United Nations Committee on the Elimination of Racial Discrimination, cited “credible reports” that China had turned the western region into “something resembling a massive internment camp, shrouded in secrecy,” according to reports by Associated Press.

Earlier, Yu Jianhua, China’s ambassador to the United Nations in Geneva, pointed to economic progress and improved living standards in the region.

Xinjiang, a Chinese region the size of Alaska, has become one of the world’s most heavily policed places. Bloomberg reported in January on government experiments with facial recognition systems that alert authorities when targeted people venture more than 300 meters (1,000 feet) beyond designated “safe areas.”

Local governments have also ordered residents to install satellite-tracking systems in their cars, while people must submit to facial scans to enter markets, buy fuel or visit places such as the capital Urumqi’s main bus terminal.

China’s President Xi Jinping said the country should “strike first” against Islamist extremism after deadly attacks involving Uighurs in 2013 and 2014, as well as reports of some fighting in Syria.

Asked about the re-education camps in a regular briefing on July 27, China’s Foreign Ministry spokesman Geng Shuang said: “The Chinese government fully respects people’s religious freedom, and we guarantee that in accordance with law. All ethnic groups and the people in all regions in China enjoy full freedom of religious belief.”

To contact Bloomberg News staff for this story: Peter Martin in Beijing at pmartin138@bloomberg.net

To contact the editors responsible for this story: Daniel Ten Kate at dtenkate@bloomberg.net, John McCluskey

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