BEIJING • When English-language state media CGTN released a video two weeks ago on Xinjiang's counter-terrorism campaign, it called the documentary an "expose" featuring never-before-seen graphic footage of a few attacks, including knife-wielding assailants slashing people at a Kunming railway station in 2014 that left 31 dead.

That was followed by a second-parter on the "black hand", the East Turkestan Islamic Movement, an Islamic extremist organisation that China said was responsible for hundreds of violent attacks in Xinjiang in recent times.