The Berlin-based European Centre for Constitutional and Human Rights (ECCHR) on Sept. 6 filed a complaint to German prosecutors, accusing retailers including Hugo Boss of abetting and profiting directly or indirectly from forced labour in the Xinjiang Uighur Autonomous Region of China’s cotton trade, Reuters reports.

The US has accused China of detaining more than 1 million Uighurs and other ethnic and religious minorities in “re-education” internment camps, where forced labour is reportedly carried out. China continues to deny these allegations. In January, the US banned imports of cotton products from Xinjiang; in July, French prosecutors reportedly launched an inquiry into fashion retailers like Uniqlo’s French unit, Inditex, SMCP and Skechers on the grounds of concealing crimes against humanity in the region.

The ECCHR’s filing is looking to open an inquiry that holds retailers to account and raise awareness of issues among consumers.

“We assume that our values and standards have been complied with in the manufacture of our goods and that there are no legal violations. We therefore reject any other assertions made by ECCHR,” a Hugo Boss spokesperson told Reuters, adding that the brand requires contractors to confirm their observance of fair working conditions throughout its supply chain.

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What the Latest Clampdown on Xinjiang Cotton Means for Fashion

New policies on both sides of the Atlantic mean businesses will likely have to prove their supply chains do not pass through the Chinese region, where the reported detention of Uighurs in forced labour camps is rife.