PANAMA CITY (AP) — Panama’s Supreme Court ruled late Thursday that the concession held by a subsidiary of Hong Kong’s CK Hutchison Holdings to operate ports at either end of the Panama Canal was unconstitutional, an outcome that advances a U.S. aim to block any influence by China over the strategic waterway.

The court’s ruling followed an audit by Panama’s comptroller, which alleged irregularities in the 25-year extension of the concession granted in 2021.

The Trump administration made blocking China’s influence over the Panama Canal one of its priorities in the hemisphere. Panama was U.S. Secretary of State Marco Rubio’s first overseas stop as the United States’ top diplomat.

Despite the insistence by Panama’s government and the canal authority that China has no influence over its operations, Rubio made clear that the U.S. viewed the operation of the ports as a national security issue for the U.S. Trump had gone so far as to say Panama should return the canal to U.S. control.