Japanese brands Muji and Uniqlo have become the latest to be embroiled in the escalating controversy over cotton sourced from China’s Xinjiang region.

Ryohin Keikaku Co., the operator of the Muji chain of minimalist furniture and lifestyle stores, saw its shares tumble after it issued a statement saying it was "deeply concerned” about reports of human rights abuses in the area, while several Chinese celebrities abruptly cut ties with Uniqlo, the clothing brand owned by Fast Retailing Co.

The firms join the likes of Hennes & Mauritz AB and Nike Inc., which have both seen their shares slammed after facing calls to boycott their products from Chinese users online due to their stance on forced labor in the region.