He was unconvinced. Last month the coronavirus swept through at least four prisons in three provinces in eastern China, infecting more than 500 inmates and guards. So far no prison cases have been reported in Xinjiang, which has one of the country’s highest concentration of prisons in addition to the network of indoctrination camps.

The Xinjiang authorities have dismissed concerns that they were hiding information about the outbreak. A spokesman for the regional government called suggestions that the new coronavirus had taken hold in the camps or that the authorities were hiding the extent of infections “fabricated slanders and attacks,” the state-run news broadcaster, China Central Television, reported.

Even before the outbreak spread in China, Xinjiang was already under its own clampdown. The region is dotted with checkpoints to control the movement of minority populations and many Muslims have been rounded up and placed in camps or prisons for a range of behavior the government has deemed extremist.

Uncensored information from the region is scarce. For Uighurs and other minorities, communicating with people abroad is grounds to be sent to a camp. Reporting on the ground is highly restricted, and the extent of the vast campaign there has been pieced together in recent years only through the testimony of exiles and former detainees, leaked documents and satellite imagery of the growing network of detention facilities.

After the first coronavirus cases in Xinjiang were reported on Jan. 23, the region beefed up its controls. Reports from Uighur exiles described how the lockdown placed Uighurs in Xinjiang at risk of starvation. The Uyghur Human Rights Project, a Washington-based advocacy organization, reviewed a pair of videos from the region last month that showed people complaining of being unable to get food.