KAMPALA—Illegally acquired and exported gold from the mineral-rich eastern Congo is fueling high-level corruption in the country’s military and bloodshed by rebel groups, an advocacy group said.

Insurgents and elements of government forces in the Democratic Republic of Congo control some 65% of the country’s gold mines, which are the foundation for an international smuggling network worth an estimated $400 million a year, the Enough Project said in a report issued Thursday.

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