THE HAGUE, Netherlands — Mexico made an emergency appeal to the U.N.'s highest court Thursday to block the execution of its citizens on death row in the U.S.

Mexico's chief advocate Juan Manuel Gomez-Robledo said the U.S. was "in breach of its international obligations" by disregarding a 2004 judgment by the U.N.'s International Court of Justice, which ruled Mexicans were denied the right to consular advice after their arrests, as guaranteed by an international treaty.

The court, informally known as the World Court, has ruled that the Mexicans were entitled to "review and reconsideration" of their trials and sentences to determine whether the violation of the 1963 Vienna Convention affected their cases.

President Bush accepted the judgment and asked state courts to review the cases.

Texas refused, and the issue went to the U.S. Supreme Court, which ruled last March by a 6-3 vote that Bush lacked the authority to compel state courts to comply with the judgment from The Hague. The Vienna Convention cannot be binding on the states unless Congress enacts legislation enforcing it as federal law, the Supreme Court said.

Mexico asked the World Court for an "interpretation" of its earlier ruling to clarify what it meant when it asked the U.S. to "review and reconsider" the cases of the condemned prisoners, and in the meantime to order the halt of the execution timetable.

Gomez-Robledo said that without urgent action now, five Mexican nationals "will be executed before the conclusion of these proceedings."

U.S. representatives were due to respond later Thursday before the 13-member tribunal.

Sandra Babcock, representing Mexico, said the World Court's decision four years ago referred to 51 Mexican nationals. Since then, 33 had sought reviews of their cases in state courts.

Only one request was granted, Babcock said. A second inmate accepted a life sentence in exchange for waiving his claim for a review.

"All other efforts to enforce the judgment have failed," she said.

Mexico listed five of its citizens slated to die. The first, on Aug. 5, is Jose Medellin, 33, condemned in the gang rape and murder of two teenage girls 15 years ago.

Texas authorities have said Medellin's case has been reviewed by state and federal courts and that he had been given the same right as any American citizen.

But Mexico said in its appeal to the World Court that the U.S. obligation to follow international law also applies to individual states. "The United States cannot invoke municipal law as justification for failure to perform its international legal obligations," it said.

The International Court of Justice is the U.N.'s judicial arm for resolving legal disputes among member states. Its decisions are binding and not subject to appeal, and only rarely have they been defied. Though it has no power of enforcement, the court can report any failure to abide by its decisions to the Security Council.