Nike and H&M are facing a backlash in China after they expressed concern about the alleged use of forced Uighur labour in the production of Xinjiang cotton.
Many Chinese have called for boycotts, celebrities have cut ties, and e-commerce platforms have dropped H&M, reports the BBC.
It comes as several Western countries imposed sanctions on China this week, accussing of committing serious human rights violations against the Uighur Muslim minority in Xinjiang.
The sanctions, including travel bans and asset freezes, target senior officials in the north-west region.
Both companies had said in separate statements that they were "concerned" about reports that Uighurs were being forced to pick cotton in Xinjiang, and that they did not source products from the region.
But the latest furore appears to have been sparked by a recent social media post by the Communist Youth League, a Chinese Communist Party group.
"Spreading rumours to boycott Xinjiang cotton, while also wanting to make money in China? Wishful thinking!" it said on microblogging platform Weibo on Wednesday morning, as it shared screenshots of H&M's statement.
State media outlets have since launched campaigns defending Xinjiang cotton and criticising the brands.
Chinese state media CGTN shared a video on Weibo claiming to show the reality of cotton-picking in Xinjiang, which involved automation and quotes from a Uighur farmer saying that people "fought" to work there for high earnings.
Chinese state broadcaster CCTV said that H&M had "miscalculated" in trying to be a "righteous hero", and that it "must pay a heavy price for its wrong actions".