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A mobile app used by police to track citizens in China’s far west region of Xinjiang shows how some of the country’s biggest technology companies are linked to a mass surveillance system that is more sophisticated than previously known, according to a report from Human Rights Watch.

The app uses facial recognition technology from a firm backed by Alibaba Group Holding to match faces with photo identification and cross-check pictures on different documents, the New York-based group said on Thursday. The app also takes a host of other data points -- from electricity and smartphone use to personal relationships to political and religious affiliations -- to flag suspicious behaviour, the report said.

The watchdog’s report sheds new light on the vast scope of activity China is monitoring as it cracks down on its minority Muslim Uighur population in a bid to stop terrorism before it happens. The U.S. State Department says as many as two million Uighurs are being held in camps in Xinjiang, a number disputed by Chinese authorities even though they haven’t disclosed a figure.

In an address on Tuesday, U.S. Secretary of State Michael Pompeo urged corporate America to think twice before doing business in Xinjiang. We watch the massive human rights violations in Xinjiang where over a million people are being held in a humanitarian crisis that is the scale of what took place in the 1930s, he said, according to comments released by the State Department. Human Rights Watch said that so-called data doors at checkpoints may be vacuuming up information from mobile phones from unsuspecting citizens. Some Xinjiang residents who suspected their phones were being used as monitoring devices even buried them in the desert, a move that could later hurt them if the system loses track of their phone, according to Maya Wang, a China researcher for Human Rights Watch.

Prevent terrorism

The political re-education camps are one pen, but then you have a series of bigger pens that are like virtual fences, Wang said. Chinas State Council Information Office did not reply to a request for comment sent by fax. The government has said the surveillance measures in Xinjiang are necessary to prevent terrorism and grow the regions economy.

Human Rights Watch said information in the report is based on reverse-engineering the police app, which communicates with a database known as Integrated Joint Operations Platform, or IJOP. The group said it enlisted Berlin-based cyber security firm Cure53 to conduct a technical assessment of the app after finding that it was publicly available online last year.

IJOP is mainly a tool for data collection, filing reports and prompting investigative missions by police. The report called for China to shut down the database behind the app, and for foreign governments to impose targeted sanctions such as visa bans and asset freezes against leaders in Xinjiang.

Human Rights Watch said the mobile app was developed by a unit of state-owned China Electronics Technology Group Corp, a Fortune 500 company known as CETC with $30 billion in revenue and 169,000 employees. The group has expanded its various operations abroad, from developing smart city solutions in Tehran to a cooperation agreement with German engineering group Siemens.

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