For years China’s censors have relied on a trusted tool kit to control the country’s internet. They have deleted posts, suspended accounts, blocked keywords, and arrested the most outspoken.

Now they are trying a new trick: displaying social media users’ locations beneath posts.

Authorities say the location tags, which are displayed automatically, will help unearth overseas disinformation campaigns intended to destabilize China. In practice, they have offered new fuel for pitched online battles that increasingly link Chinese citizens’ locations with their national loyalty. Chinese people posting from overseas, and even from provinces deemed insufficiently patriotic, are now easily targeted by nationalist influencers, whose fans harass them or report their accounts.