Chinese police are using a mobile app to keep data on millions of ethnic Uighurs in Xinjiang province, according to Human Rights Watch (HRW).
In a report released on Thursday, HRW said it had reverse engineered the app to see how mass surveillance worked.
The app is used to closely monitor behaviours, it said, including lack of socialising, using too much electricity or having acquaintances abroad.
Rights groups say Uighur Muslims are being severely persecuted in China.
The UN has said there are credible reports up to a million Uighurs are being held in detention in Xinjiang, in what China says are “re-education centres”.
In particular, it targets “36 person types” that authorities should pay attention to.
These include people who seldom use their front door, use an abnormal amount of electricity and those that have gone on Hajj – an Islamic pilgrimage – without state authorisation.
The report does not make explicit mention of any ethnic groups specifically targeted, but the “36 person types” include “unofficial” imams – Islamic leaders – and those who follow Wahhabism, an Islamic doctrine.
