WASHINGTON -- The United States is imposing a region-wide ban on all cotton and tomato products from western China's Xinjiang region over allegations that they are made with forced labor from detained Uighur Muslims, U.S. Customs and Border Protection said on Wednesday.

The action applies to raw fibers, apparel and textiles made from Xinjiang-grown cotton, as well as tomato-based food products and seeds from the region. The ban, knows 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 Department of Homeland Security (DHS), estimates that about $9 billion of cotton products and $10 million worth of tomato products were imported into the United States in the past year.

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

In December, the U.S. Congress passed the bipartisan Uyghur Forced Labor Prevention Act that assumes that all goods manufactured in Xinjiang are made with forced labor and therefore banned under the 1930 Tariff Act, unless the commissioner of U.S. Customs and Border Protection certifies otherwise.

The move is the latest by the Trump administration in its final days to harden the U.S. position against Beijing, erecting economic penalties that would make it more difficult for President-elect Joe Biden to ease U.S.-China tensions after he takes office on Jan. 20.

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

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

The United Nations cites what it says are credible reports that 1 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 centers needed to fight extremism. Beijing has rejected allegations of forced labor as "false news...to suppress Chinese firms and China." 

(Reporting by David Lawder, additional reporting by David Brunnstrom; Editing by Franklin Paul and Alistair Bell)