The United Nations has denounced "serious human rights violations" in the Chinese region of Xinjiang and sees possible "crimes against humanity".
According to a report by outgoing UN Human Rights Commissioner Michelle Bachelet on the situation of the Muslim Uyghur minority in Xinjiang, published on Thursday night, there are "credible" allegations of torture.
The "extent of arbitrary and discriminatory detention" of Uyghurs and members of other majority Muslim groups may constitute "international crimes, particularly crimes against humanity," the report said.
The document was released just minutes before Bachelet's term ended at midnight.
For years, the communist leadership in Beijing has been accused of systematically suppressing the Uyghur population and other Muslim minorities in the Xinjiang region.
Human rights activists have been frustrated by the report's delay - Bachelet had said almost a year ago that her office was in the process of finalizing the report.
Last week she spoke of "enormous pressure" from all sides on the occasion of the announced publication of the document.
China had resisted publication of the human rights report.
A spokesman for China's foreign ministry on Wednesday called the report a "farce orchestrated by the United States and a small number of Western powers."
China also regularly denies allegations of human rights violations in Xinjiang.