Bangladesh, Dec. 15 -- The United States has issued one of its strongest warnings yet to Fiji, threatening to downgrade the Pacific island nation to the lowest possible tier on Washingtons global human trafficking index unless authorities take decisive action against the Grace Road Group, a South Korean religious sect accused of human trafficking, forced labor, and other serious abuses. The move, confirmed by a US State Department official speaking to the Organized Crime and Corruption Reporting Project (OCCRP), could jeopardize millions of dollars in development assistance and significantly alter Fijis economic and diplomatic outlook.

At the center of the dispute is the State Departments annual Trafficking in Persons (TIP) report, which...