United States Customs and Border Protection alleges the goods are made with forced labour from detained Uighur Muslims.

The United States is imposing a region-wide ban on all cotton and tomato products from China’s western Xinjiang region over allegations that they are made with forced labour from detained Uighur Muslims, US Customs and Border Protection (CBP) said on Wednesday.

The action applies to raw fibres, apparel and textiles made from Xinjiang-grown cotton, as well as tomato-based food products and seeds from the region. The ban, known as a withhold release order, also applies to products processed or manufactured in third countries, CBP officials told a news briefing.

The agency, which is part of the US Department of Homeland Security (DHS), estimates that about $9bn of cotton products and $10m worth of tomato products were imported into the US in the past year.

DHS acting deputy secretary Kenneth Cuccinelli said the order sends a message to importers that “DHS will not tolerate forced labour of any kind” and companies should eradicate Xinjiang products from their supply chains.

In December, the US Congress passed the bipartisan Uyghur Forced Labor Prevention Act, which assumes that all goods manufactured in Xinjiang are made with forced labour and therefore banned under the 1930 Smoot-Hawley Tariff Act, unless the CBP commissioner certifies otherwise.

The move is the latest by the administration of outgoing US President Donald Trump to harden the US position against Beijing in the administration’s final days, erecting economic penalties that would make it more difficult for President-elect Joe Biden to ease US-China tensions after he takes office on January 20.

The move follows a ban on cotton products from China’s largest producer, the Xinjiang Production and Construction Corps (XPCC). Both will have a significant impact on the cotton production in Xinjiang, which produces as much as 20 percent of the world’s supply of the commodity.

CBP officials said some 43 shipments of cotton-based products have been detained at US entry ports since the XPCC ban was announced. US apparel makers have in the past criticised a broader ban as impossible to enforce.

The United Nations cites what it says are credible reports that one million Muslims held in camps have been put to work in Xinjiang and faith leaders, activist groups and others have said crimes against humanity, including genocide, are taking place there.

China denies mistreating Uighurs and says the camps are vocational training centres needed to fight extremism. Beijing has rejected allegations of forced labour as “false news … to suppress Chinese firms and China.”