At hastily convened hearings last month, Mexico argued that the United States is defying a 2004 International Court of Justice order to review the cases of 51 Mexicans sentenced to death by state courts.

That order was based on the Hague-based court's finding that the condemned prisoners had been denied the right to help from their consulate following their arrest.

Wednesday's ruling comes less than three weeks before the first of the death row inmates, Jose Medellin, is scheduled for execution by lethal injection in Texas for taking part in the gang rape and murder of two teenage girls 15 years ago.

At last month's hearings, Mexico's chief advocate Juan Manuel Gomez-Robledo told the court the cases had not been systematically reviewed, and the U.S. was "in breach of its international obligations."

John B. Bellinger III, the U.S. legal adviser, said federal government had gone to "extraordinary lengths" to carry out the World Court's directive and to intercede with the state courts.

After the World Court's ruling, President George W. Bush issued a directive to the state courts to abide by the decision and also asked Texas specifically to review Medellin's case ahead of his planned Aug. 5 execution.