HONG KONG — As the government accelerated mass detentions of Muslim minorities in northwest China, a senior official issued a secret directive giving detailed orders for how the rapidly expanding indoctrination camps holding them should be managed.

Guards should impose pervasive, round-the-clock video surveillance to prevent escapes. Inmates were to be kept isolated from the outside world and held to a strict scoring system that could determine when they might be released. And the facilities were to be shrouded in secrecy, with even employees banned from bringing in mobile phones.

“It is necessary,” the directive from two years ago said, “to strengthen the staff’s awareness of staying secret, serious political discipline and secrecy discipline.”

Now that secrecy has been shattered with the publication of the directive itself. It is one of six internal documents obtained by the International Consortium of Investigative Journalists that shed new light on China’s crackdown in the Xinjiang region, where a million or more ethnic Uighurs, Kazakhs and others have been detained in the past three years.

The disclosure of the 24 pages of documents amounts to a second significant leak from inside China’s ruling Communist Party related to the crackdown. A member of the Chinese political establishment shared a different, 403-page set of internal papers with The New York Times earlier this year, expressing hope that it would make it more difficult for party leaders, including President Xi Jinping, to escape culpability for the mass detentions.

While the source of the new documents is unknown — they were provided by Uighur overseas networks — their disclosure may amount to another sign of dissent in the party over the crackdown.

The International Consortium of Investigative Journalists, an independent nonprofit based in Washington, led the inquiry into the documents, bringing together more than 75 journalists from the consortium and 17 partner organizations, including The Times, in 14 countries. Outside experts also reviewed the papers and concluded they were authentic.

“In terms of documentary evidence, we have reached a next level of disclosure,” said Adrian Zenz, a researcher who has studied the camps and a senior fellow in China studies at the Victims of Communism Memorial Foundation, a human rights group in Washington. “The evidence we have now is very comprehensive, very complete. It’s kind of game over for Beijing in terms of the cover-up, the denials and the half-truths.”

The most significant of the new documents is the secret directive on how to manage the camps, which is the only document in both sets of leaked papers to describe the inner workings of these facilities. The nine-page order was issued in November 2017 by the Communist Party committee in Xinjiang that oversees legal affairs.

‘Prevent escapes’

Beijing has rejected criticism of the camps and described them as job-training centers that use humane methods to fight the spread of Islamic extremism. Internally, the government often uses language consistent with that position. The leaked directive, for example, refers to the camps as “vocational skills education and training centers” and the detainees as “students.”

But it also lays bare the punitive underpinnings of these facilities, and some of its language on guarding against escapes and other incidents is identical to that used in guidelines for prisons and other detention sites.

The orders called on guards to strictly control and monitor the activities of students. “Prevent escapes while they are at class, dining, using the toilet, washing, receiving medical care or meeting with family.”

Other instructions call for erecting guardhouses and internal partitions inside the camps to prevent inmates from moving around freely; rigorously checking any people, vehicles or goods entering, and recruiting informants to spy on other detainees.

“Evaluate and resolve students’ ideological problems and abnormal emotions at all times,” the directive said.

The document included orders for “full video surveillance coverage of dormitories and classrooms free of blind spots,” and prohibited detainees from having contact with the outside world, except in strictly monitored interactions.

The government says these sites help prevent Uighurs and other Muslims from being drawn to religious extremism by teaching them the Chinese language, job skills and how to be law-abiding citizens. In response to the earlier leak of documents, the government argued that its methods have effectively stifled extremist violence in Xinjiang.

Former detainees, though, have described the classes as numbing, harsh and ultimately futile attempts at brainwashing. And residents have been sent to internment camps for behavior that would be commonplace elsewhere: traveling abroad, showing signs of religious devotion praying regularly or growing a long beard, or installing certain cellphone apps, such as encrypted messaging tools.

Mr. Zenz, the scholar who reviewed the documents, said he also obtained a cache of more than 25,000 files from government departments that provides new detail on the scale of the detentions and their impact on families.

In six villages in Yarkand, a county in southwestern Xinjiang where nearly all the residents are Uighur, he found that about one in six rural adult residents were interned or in prison. In two villages in that county, nearly 60 percent of households had at least one person in custody.

The detainees in Xinjiang are mostly working-age men, he wrote in a new paper, and that has led to hardships for families. In one case Mr. Zenz documented, five children were effectively orphaned after their father was imprisoned and their mother put in an indoctrination camp.

One of the leaked daily bulletins orders an investigation of people from Xinjiang who have obtained foreign citizenship or applied for visas or other documents at Chinese embassies abroad.

Another describes how 15,683 “suspicious persons” were sent to centers in southern Xinjiang on the week of June 19, 2017. The government has repeatedly refused to say how many people are being held in these camps.

Other bulletins reveal how the authorities settled on targets for detention by using databases that collect and collate information on Xinjiang residents, especially Uighurs and other Muslim minorities.

The daily bulletins and the document on camp operations were signed by Zhu Hailun, who was then the top security official in Xinjiang. He was assigned to another position in the regional legislature early this year.

Mr. Zhu, 61, appears to have been a key enforcer of the internment campaign, turning the orders of the regional party secretary, Chen Quanguo, into detailed plans. A party official who spent his career in Xinjiang, Mr. Zhu had previously served as the head of Xinjiang’s capital, Urumqi, succeeding an official who was fired in 2009 after bloody ethnic riots killed nearly 200 people, most of them Han Chinese.

Like many in his generation, Mr. Zhu was no stranger to the idea that minds can be reprogrammed through intense indoctrination and propaganda: He grew up in Mao’s era, when such techniques were widespread. In an official biography, Mr. Zhu described the two years he spent as a teenager working in a rural commune as a period of “re-education.”

Over 40 years later, Mr. Zhu was uncompromising as Mr. Chen’s right-hand man for security. An internal document from 2017 signed by Mr. Zhu that was among the papers leaked to The Times attributed attacks in London and Manchester in part to putting “human rights above security.”

‘Promote repentance’

The directive on camp operations instructed officials to keep extensive records on detainees, and described a scoring system that measured how they behaved to determine their fate.

Inmates should be assigned to one of three zones based on how dangerous they are judged to be — general management, strict, and very strict, the document said. But detainees could be moved between the grades of control depending on their scores.

“Break down scores and manage and individually assess the students’ ideological transformation, study and training, and compliance with discipline,” the document said.

Officials were told to assign inmates to fixed positions in dormitories, classes, lineups and workshops, and to control every detail of life inside the camps, at every moment of the day, including wake-up, meals, studies and showers.

Detainees must meet “disciplinary demands” or face punishment, the directive added.

“Strengthen the management of the students’ hygiene,” it said. “Ensure that they get timely haircuts and shave, change and wash their clothes. Arrange for them to have baths once or twice a week, so that they develop good habits.”

The demands listed in the directive echoed the accounts of former detainees like Orynbek Koksebek, an ethnic Kazakh man who spent four months in an indoctrination camp in Xinjiang after being detained by the Chinese authorities in December 2017.

“There was military discipline in everything we did, how you walk, stand up straight. If you didn’t, they would slap you,” he said in an interview in the Kazakh city of Almaty earlier this year.

A key disclosure in the leaked directive is an official description of the conditions that detainees must meet to be released from the camps. Aside from achieving a good score in the point system, the document said, inmates must be categorized at the lowest threat level and have served a minimum term of one year — though interviews with former detainees indicate that camps sometimes release people sooner.

The directive also emphasized the importance of showing remorse. Discussions with detainees should “promote the repentance and confession of the students for them to understand deeply the illegal, criminal and dangerous nature of their past behavior,” it said.

A different document, among the set shared with The Times earlier this year, described how family members outside the camps are told that their behavior can also affect when a detainee is released — a implied threat aimed at silencing complaints.

Former detainees said the criteria for release seemed arbitrary, and there was little clarity on when or why people could leave.

“You enter the camp with 1,000 points. You can’t gain points. You can only lose them if you yawn or smile,” recalled Rahima Senbai, who was held in a camp in October 2017 and only allowed to return to her home in Kazakhstan a year later. “If you ever went under 500 points, you’d have to stay for another year.”

Zharqynbek Otan, who was held in a camp for seven months after his arrest in January 2017 and has since fled China, said the goal of the detention was to impose loyalty to the Chinese state.

“The main purpose is to brainwash you,” he said, “so you forget your roots and everything about Islam and ethnic identity.”