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.

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," Ms Callamard said.

She also accused UN Secretary General António Guterres of "failing to act according to his mandate".

Mr Guterres "has not denounced the situation, he has not called for an international investigation", Ms Callamard told the BBC. "It is incumbent on him to protect the values upon which the United Nations has been founded, and certainly not to stay silent in front of crimes against humanity."

In the 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."