The human rights organisation Amnesty International has said China is committing crimes against humanity in Xinjiang, the north-western region that is home to the Uyghurs and other Muslim minorities.
In a report published on Thursday, Amnesty called on the UN to investigate, and said China had subjected Uyghurs, Kazakhs, and other Muslims to mass detention, surveillance, and torture, reports the BBC.
Agnès Callamard, the secretary general of Amnesty International, accused Chinese authorities of creating "a dystopian hellscape on a staggering scale".
"It should shock the conscience of humanity that massive numbers of people have been subjected to brainwashing, torture and other degrading treatment in internment camps, while millions more live in fear amid a vast surveillance apparatus," Callamard said.
In a 160-page report based on interviews with 55 former detainees, Amnesty said there was evidence the Chinese state had committed "at least the following crimes against humanity: imprisonment or other severe deprivation of physical liberty in violation of fundamental rules of international law; torture; and persecution."
The report follows a similar set of findings by Human Rights Watch, which said in an April report that it believed the Chinese government was responsible for crimes against humanity.
China has been accused by some Western nations and rights groups of pursuing a genocide against the Turkic ethnic groups in Xinjiang - though there is dispute over whether the state's actions constitute a genocide.
The author of the Amnesty report, Jonathan Loeb, said at press conference on Thursday that the organisation's research "did not reveal that all the evidence of the crime of genocide had occurred" but that it had so far "only scratched the surface".
China routinely denies all accusations of human rights abuses in Xinjiang.