Chinese officials have sent out a notice instructing Muslim citizens to install a ‘surveillance app’ on their phones, and are conducting spot checks in the region to ensure that residents have it, Mashable reported.According to Radio Free Asia reports, the notice was issued over a week ago after China ramped up surveillance measures in Xinjiang, home to much of the minority population. WeChat sent the notice, written in Uyghur and Chinese, to residents in Urumqi, Xinjiang's capital.Android users were asked to scan the QR code to install the ‘Jingwang app’ that would, as Chinese officials claimed, "automatically detect terrorist and illegal religious videos, images, e-books and electronic documents" stored on the phone. If illegal content was detected, users would be ordered to delete it, said the notice. Users who deleted, or did not install the app, would be detained for up to 10 days, according to social media users.The Jingwang app reportedly scans for the MD5 digital signatures of media files on the phone and matches them to a stored database of offending files classified by the government as illegal ‘terrorist-related’ media. It also keeps a copy of Weibo and WeChat records, as well as a record of IMEI numbers, SIM card data and Wifi login data. The records are then sent to a server.The move is the latest in digital surveillance in Urumqi. In March, government workers were asked to sign an agreement have ‘terrorist-related’ media content, while the police sprung a surprise spot check on a group of nursing students."Chinese police are so powerful, particularly in Xinjiang, [that] anyone being stopped is unlikely to be able to refuse the police's requests," said Maya Wang, a senior researcher at Human Rights Watch."The authorities have a lot of explaining to do about this software, including what it does," she added. "While the authorities have the responsibility to protect public safety, including by fighting terrorism, such mass collection of data from ordinary people is a form of mass surveillance, and an intrusion to privacy."Xinjiang has a population of eight million Uyghurs, a Turkic ethnic group. Its people have complained of longstanding oppression under the country's Communist government.In March, the government banned veils and the growing of long beards — traditional Muslim customs. Last year, Xinjiang residents who used foreign messaging apps such as Whatsapp found they had their phone services cut.This story originally appeared on Mashable