BEIJING—China has mandated the use of body cameras or other video recorders by a law-enforcement agency often accused of thuggish behavior, in a bid to mute criticism with an unusual embrace of transparency.

China’s chengguan, or urban-management officers, handle nonpolice matters such as enforcing sanitation rules and keeping sidewalks clear. A reputation for violence has made them a lightning rod for public ire, particularly in the smartphone era when accusations often come with visual evidence.

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