China violated trade law by restricting exports of raw materials crucial for industrial production, trade judges have ruled.
China's export duties were "inconsistent" with commitments the country had agreed to in its protocol of accession, the World Trade Organization (WTO) said in a statement.
"The panel also found that export quotas imposed by China on some of the raw materials were inconsistent with WTO rules," it added.
The ruling is a victory for the United States, the European Union and Mexico, who took China to the WTO in 2009.
They had argued that restrictions on mineral exports such as bauxite and magnesium discriminated against foreign manufacturers and gave an unfair advantage to domestic producers using them.