Human rights activists claim more than one million Uighurs along with other ethnic minorities have been unjustly arrested and imprisoned in China's Xinjiang province.
Obtained by the International Consortium of Investigative Journalists (ICIJ) and published by 17 media outlets, the documents showed the strict protocols governing life in the camps.
In one document, local officials are told to monitor inmates at all times - including during toilet breaks - to prevent escape. Staff are also banned from befriending inmates and engaging in "personal interactions" to prevent "collusion", the document read.
The leak comes one week after The New York Times reported, based on more than 400 pages of internal papers it had obtained, .
They are just the latest development in what Amnesty International calls the "systematic repression" of the Uighur people by China.
Who are the Uighurs?
Uighurs are a Muslim Turkic minority mostly based in the Xinjiang province in China's far north-west. They make up around 45 per cent of the population there.
The Uighurs are one of the largest ethnic minority populations in China, with an estimated 11 million Uighurs living in Xinjiang - half the Muslim population in China.
Xinjiang was designated an official autonomous region by the Communist party in 1955, like Tibet to its south, in recognition of its distinct history and ethnic identity.
A Map of Xinjiang. Source: Google Maps
What is happening to the Uighurs?
The most controversial aspect of China's security crackdown in Xinjiang is its vast network of re-education camps, where human rights groups and former inmates say detainees are subject to forced political indoctrination and even abuse.
A Kazakh businessman, who spent nearly two months in a camp, said the facilities only had one goal: to strip detainees of their religious belief.
Inmates were forced to sing patriotic songs every morning and eat pork, a violation Islam's religious restrictions, he said.
Uighurs detained in the Kashgar City Detention Centre in China. Source: YouTube
An AFP investigation of over 1,500 government documents last year also found that Xinjiang camps were run more like jails than schools as claimed by Beijing.
Tasers, tear gas, and even "tiger chairs" - used by Chinese police to restrain interrogation subjects - were among items requested by centres around Xinjiang.
Still, the Chinese government has defended what it calls "vocational education centres" as a necessary countermeasure for religious extremism, despite denying their existence until last October.
What happens outside the camps?
Outside of the camps, local residents in Xinjiang are tightly monitored by an array of high-tech surveillance systems.
A mobile app called the Integrated Joint Operations Platform collects information from multiple sources, including facial-recognition cameras, wifi sniffers, and home visits in the region, according to Human Rights Watch.
Xinjiang authorities use the app to target specific individuals, such as those who donate to mosques "enthusiastically", do not socialise with neighbours, and do not use a smartphone, the group found.
In April, a report by The New York Times also revealed that Chinese authorities are using a vast system of facial recognition to track Uighurs across the country.
In the central Chinese city of Sanmenxia, Chinese authorities scanned whether residents were Uighurs 500,000 times in one month alone, according to the newspaper.
Data leaks have also offered clues to the scale of surveillance across all ethnic groups.
Within a 24-hour period, more than six million locations were saved by tracking devices in Xinjiang, according to a Dutch security researcher who discovered an exposed database in February.
Uighur security personnel patrol near the Id Kah Mosque in Kashgar in western China's Xinjiang region in 2017. Source: AAP
The database also stored a range of personal information on 2.6 million people in the region, including ethnicity, address, and employer.
What other restrictions are there on Uighurs?
In 2017, Xinjiang authorities passed sweeping "anti-extremism" regulations that banned a wide range of behaviours and customs - formalising a regional crackdown on certain Muslim practises.
Growing "abnormal" facial hair was included in the government's list, as well as wearing robes that cover the whole body and face.
The new regulations also required Uighurs to watch or listen to government propaganda on radio or TV.
A Uighur woman protests before a group of paramilitary police in China's Xinjiang region. Source: AAP
A visit to Xinjiang during the month of Ramadan by journalists also showed profound changes in Uighur-dominant cities like Kashgar, where a sunrise prayer call used to echo throughout the city.
This year, the celebration of Eid al-Fitr was a quiet affair, with locals filing into the city's state-approved mosque as police and officials fenced off the surrounding area.
Since 2017, dozens of mosques and religious sites around Xinjiang have also been demolished or stripped of their domes, according to satellite images.
What happens to Uighurs overseas?
Beijing's push to control the Uighur population has also extended well beyond Chinese borders.
In July 2017, Egyptian authorities aided Chinese officials in a police raid targeting Uighurs in the country.
Uighurs in countries as far away as the US have also told reporters they have received menacing messages and explicit threats to relatives in Xinjiang - part of China's powerful state security apparatus's bid to silence activists and recruit informants.
One man said he remains reluctant to speak publicly despite now being a New Zealand citizen because he fears for himself and his 78-year-old mother.
After Shawudun Abdughupur refused to give details of his meetings with other Uighurs, he received this chilling message: "We can find you. We are in New Zealand."
