Chinese authorities are monitoring the Uighur population's everyday movements and behaviour and sending people to internment camps over facial hair and having too many babies, leaked documents have revealed.
In one case, authorities sent a Uighur man to a "re-education camp" and monitored 15 of his relatives after he grew a long beard.
Officials concluded that the man's facial hair and his wife's use of a veil indicated they had been "infected with religious and extremist ideas", it is claimed.
The 137-page document handed to German news channel DW and the BBC is said to list 311 people who were sent off for "re-education" in the county of Karakax in 2017 and 2018.
Reasons given for detention include fasting, growing a beard, applying for a passport and breaching official birth policy by having too many children.
It lists personal details of more than 3,000 individuals from the far western region of Xinjiang, including the full names and identification numbers of more than 1,800 family members, neighbours and friends connected to the 311 sent to the Karakax camp.
Children are also said to feature on the list.
It provides details of downloaded videos and internet chat messages, high-tech surveillance with facial recognition cameras and the widespread use of spies, house visits and interrogations.
"The level of detail is overwhelming," Rian Thum, an expert at the University of Nottingham, told DW. "I think it is interesting to imagine that these things exist across Xinjiang. The data that is out there must be staggering."
While most of the detainees were later approved for release - albeit under constant surveillance – dozens were forced to work in factories, according to the documents.
Up to two million Uighur Muslims and other ethnic minorities have been detained in camps as part of a supposed counterterrorism campaign since 2014.
China has insisted it is running what it calls "vocational training" centres to combat extremism in the region. However, former detainees have alleged inmates are subjected to torture, medical experiments and gang rape.
Last month it emerged that more than 100 Uighur graveyards had been demolished by the authorities in what human rights groups described as an escalation of the communist regime's campaign to destroy the Muslim minority's culture.