More from the AP:
Mexico contends the United States is defying a 2004 order by the International Court of Justice to review the cases of 51 condemned Mexican prisoners.
That ruling said the inmates had been denied the right to help from their consulate after their arrests. It said the death row prisoners were entitled to a reconsideration of their trials and sentences to determine whether the violation affected their cases.
Informally known as the World Court, the tribunal is the U.N.'s judicial arm for resolving disputes among nations. Its decisions are binding and final, but it has no enforcement powers.
Sandra Babcock, representing Mexico, said that since the court's decision four years ago, 33 Mexicans had sought reviews of their cases in state courts.
Only one request was granted, Babcock said. A second inmate accepted a commutation to life imprisonment 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 for imminent execution, all in Texas. Medellin, 33, was sentenced to death in the gang rape and murder of two teenage girls 15 years ago.