Hundreds of thousands of ethnic minority laborers in China's northwestern Xinjiang region are being forced into picking cotton by hand through a coercive state labor scheme, a report has said.
Rights activists have said the northwestern Xinjiang region is home to a vast network of extrajudicial internment camps that have imprisoned at least one million people, which China has defended as vocational training centres to counter extremism.
A report by Washington-based think tank the Center for Global Policy published Monday -- which referenced online government documents -- said that in 2018 three majority-Uighur regions within Xinjiang sent at least 570,000 people to pick cotton as part of a state-run coercive labour transfer scheme.
Researchers estimate that the total number involved in coerced Xinjiang cotton-picking -- which relies heavily on manual labour -- exceeds that figure by "several hundred thousand".
Xinjiang is a global hub for the crop, producing over 20 percent of the world's cotton, with the report warning of the "potentially drastic consequences" for global supply chains.
Around a fifth of the yarn used in American comes from Xinjiang.
Beijing said that all detainees have "graduated" from the centres, but reports have suggested that many former inmates have been transferred to low-skilled manufacturing factory jobs, often linked to the camps.
But the think tank report said labour transfer scheme participants are heavily surveilled by police, with point-to-point transfers, "military-style management" and ideological training, citing government documents.
"It is clear that labour transfers for cotton-picking involve a very high risk of forced labour," Adrian Zenz, who uncovered the documents, wrote in the report.
"Some minorities may exhibit a degree of consent in relation to this process, and they may benefit financially. However... it is impossible to define where coercion ends and where local consent may begin."
The report also says there is a strong ideological incentive to enforce the scheme, as the boost in rural incomes allows officials to hit state-mandated poverty alleviation targets.
China has strongly denied allegations of forced labour involving Uighurs in Xinjiang, and accused the US of wanting to "suppress Xinjiang companies".
Beijing also says training programmes, work schemes and better education have helped stamp out extremism in the region.
Earlier this month, the US banned imports of cotton produced by the Xinjiang Production and Construction Corps, a major paramilitary entity, which covers about a third of the crop produced in the entire region.
Another proposed bill banning all imports from Xinjiang has yet to pass the US Senate.
Several international brands including Adidas, Gap and Nike have been accused of using Uighur forced labour in their textile supply chains, according to a March report by the Australian Strategic Policy Institute.