Since last spring, Chinese authorities in the heavily Muslim region of Xinjiang have imprisoned tens, possibly hundreds of thousands of Muslim Chinese — and even foreign citizens — in mass internment camps.

Key points: US State Department estimates detainees "at the very least in the tens of thousands"

US State Department estimates detainees "at the very least in the tens of thousands" Detainees who most vigorously criticise the people and things they love are rewarded

Detainees who most vigorously criticise the people and things they love are rewarded Those who refuse are punished with solitary confinement, beatings and food deprivation

This detention campaign has swept across Xinjiang in what a US commission on China last month said was "the largest mass incarceration of a minority population in the world today".

Omir Bekali, a Kazakh Muslim, and other former detainees told the Associated Press how they had to disavow their Islamic beliefs, criticise themselves and their loved ones and give thanks to the ruling Communist Party.

When Mr Bekali refused to follow orders each day, he was forced to stand at a wall for five hours at a time.

A week later, he was sent to solitary confinement, where he was deprived of food for 24 hours. After 20 days in the heavily-guarded camp, he wanted to kill himself.

"The psychological pressure is enormous, when you have to criticise yourself, denounce your thinking — your own ethnic group," said Bekali, who broke down in tears as he described the camp.

"I still think about it every night, until the sun rises. I can't sleep.

"The thoughts are with me all the time."

Chinese officials have largely avoided commenting on the camps, but some are quoted in state media as saying ideological changes are needed to fight separatism and Islamic extremism.

Radical Muslim Uighurs have killed hundreds in recent years, and China considers the region a threat to peace in a country where the majority is Han Chinese.

Life inside 're-education camps'

Omir Bekalic, centre, prepares to pray at a mosque in Almaty, Kazakhstan.

The internment program aims to rewire the political thinking of detainees, erase their Islamic beliefs and reshape their very identities.

The camps have expanded rapidly over the past year, with almost no judicial process or legal paperwork.

Detainees who most vigorously criticise the people and things they love are rewarded, and those who refuse to do so are punished with solitary confinement, beatings and food deprivation.

The recollections of Mr Bekali, 42, offer what appears to be the most detailed account yet of life inside so-called re-education camps.

The Associated Press also conducted rare interviews with three other former internees and a former instructor in other centres who corroborated Mr Bekali's depiction.

Most spoke on condition of anonymity to protect their families in China.

Mr Bekali's case stands out because he was a foreign citizen, of Kazakhstan, and was seized by China's security agencies and detained for eight months last year without recourse.

Although some details are impossible to verify, two Kazakh diplomats confirmed he was held for seven months and then sent to re-education.

Beijing's attempts at 'Cultural cleansing'

A screen shows Chinese President Xi Jinping in Hotan in western China's Xinjiang region. ( AP: Ng Han Guan, File )

The detention program is a hallmark of China's emboldened state security apparatus under the deeply-nationalistic, hard-line rule of President Xi Jinping.

It is partly rooted in the ancient Chinese belief in transformation through education — taken once before to terrifying extremes during the mass thought reform campaigns of Mao Zedong, the Chinese leader sometimes channelled by Mr Xi.

"Cultural cleansing is Beijing's attempt to find a final solution to the Xinjiang problem," James Millward, a China historian at Georgetown University, said.

Rian Thum, a professor at Loyola University in New Orleans, said China's re-education system echoed some of the worst human rights violations in history.

"The closest analogue is maybe the Cultural Revolution in that this will leave long-term, psychological effects," Thum said. "This will create a multigenerational trauma from which many people will never recover."

The detention program evokes the mass thought reform campaigns of Mao Zedong. ( Reuters: Thomas Peter )

Asked to comment on the camps, China's Foreign Ministry said it "had not heard" of the situation.

When asked why non-Chinese had been detained, it said the Chinese Government protected the rights of foreigners in China and they should also be law-abiding.

Chinese officials in Xinjiang did not respond to requests for comment.

However, bits and pieces from state media and journals show the confidence Xinjiang officials hold in methods they say work well to curb religious extremism.

China's top prosecutor, Zhang Jun, urged Xinjiang's authorities this month to extensively expand what the Government calls the "transformation through education" drive in an "all-out effort" to fight separatism and extremism.

Detainees estimated to be at least in the 'tens of thousands'

A banner on a mosque reads "Love the party, love the country" in Kashgar, in western China's Xinjiang region. ( AP: Ng Han Guan, File )

In a June 2017 paper published by a state-run journal, a researcher from Xinjiang's Communist Party School reported most of 588 surveyed participants did not know what they had done wrong when they were sent to re-education.

But by the time they were released, nearly all — 98.8 per cent — had learned their mistakes, the paper said.

Transformation through education, the researcher concluded, "is a permanent cure".

All-encompassing, data-driven surveillance tracked residents in Xinjiang with around 12 million Muslims, including ethnic Uighurs and Kazakhs.

Viewing a foreign website, taking phone calls from relatives abroad, praying regularly or growing a beard could land one in a political indoctrination camp, or prison, or both.

The new internment system was shrouded in secrecy, with no publicly available data on the numbers of camps or detainees.

The US State Department estimated those being held were "at the very least in the tens of thousands".

A Turkey-based TV station run by Xinjiang exiles said almost 900,000 were detained, citing leaked government documents.

AP