US Customs and Border Protection (CBP) has issued an order to detain imports of copper and copper products from Serbia’s Chinese-owned mining company, Zijin Copper, over suspicions the goods were produced using forced labour, the agency said on June 16.

Zijin Copper operates one of Serbia’s key copper mining and processing facilities, and the US measure could disrupt its access to the American and other markets.

The Withhold Release Order (WRO), effective immediately, instructs US customs officers to stop shipments of copper products made by Serbia Zijin Copper D.O.O. at all US ports of entry.

CBP said the order was issued under a US law prohibiting the import of goods produced with forced labour, adding it was the fourth such measure taken in fiscal year 2026.

“When CBP has evidence that imported goods were produced by forced labor, the agency detains those shipments through a WRO order,” it said in a statement.

The agency said its decision followed an investigation that found indications of forced labour practices at the company. Evidence reviewed included worker testimonies, photographs, field reports, text message screenshots, as well as findings from NGOs, media and academic research.

According to CBP, the evidence suggests workers at Serbia Zijin Copper were exposed to six indicators of forced labour identified by the International Labour Organization, including abuse of vulnerability, withholding of wages, intimidation and threats, restriction of movement, retention of personal documents and excessive overtime.

The move follows a similar action in December 2025, when CBP issued a WRO against products from a Chinese-owned tyre factory in Zrenjanin, Serbia, citing evidence of forced labour.

Serbia has faced repeated allegations of labour abuses at Chinese-owned industrial sites in recent years, including in the mining and manufacturing sectors. Rights groups, international organisations and media have documented cases involving foreign workers subjected to poor living conditions, withheld wages, passport confiscation and excessive overtime.

Such concerns were also highlighted in the US State Department’s 2025 Trafficking in Persons Report, which pointed to ongoing risks of labour exploitation in the country.