More than half a million people from ethnic minority groups in the region have been coerced into cotton picking, according to a new report from Washington-based think tank the Center for Global Policy, which suggests the impact on the cotton supply chain of China’s controversial labour transfer scheme runs deeper than previously thought.

Xinjiang is a major cotton-producing region, accounting for 20 percent of global supply. But it is also the focus of international scrutiny over the alleged coercion of ethnic minorities into forced labour.

Earlier this month, the US banned cotton imports from the Xinjiang Production and Construction Corps, a paramilitary organisation that counts as one of China’s largest cotton producers. The Chinese Ministry of Foreign Affairs has said the allegations are “completely fabricated.”