UPDATE 1-Japan's Mizuno and World Co to stop using Xinjiang cotton -Nikkei

(Adds background, response from companies)

TOKYO, May 21 (Reuters) - Japanese apparel makers Mizuno and World Co will stop using cotton from China's Xinjiang due to concerns over alleged human rights violations in the region, Nikkei reported on Friday.

Global apparel manufacturers are coming under growing criticism from consumers for ties to Xinjiang. But some firms which have said they would not use cotton produced in the region have faced a strong backlash and boycotts in China.

Activists and U.N. rights experts have accused China of using mass detainment, torture and forced labour in the region. China denies these claims and says its actions are necessary to counter extremism.

A third apparel company COX Co Ltd also decided not to use cotton from Xinjiang, Nikkei said, citing its survey of 50 Japanese apparel and sportswear makers.

Representatives at Mizuno, World Co and Cox were not immediately reachable for comment outside business hours.

In January, Fast Retailing Co Ltd's Uniqlo brand shirts were blocked at the United States border on concerns they violated a ban on cotton products produced in the Xinjiang region. (Reporting by Sakura Murakami, Ju-min Park, Ritsuko Ando, Editing by David Goodman and Kim Coghill)