The government has claimed it is illegal to kill the prisoners because they were refused their right to legal assistance from the Mexican consulate. The United States argues that granting Mexico's request to cancel the executions would violate U.S. sovereignty.

"This is a very important case for Mexico, and we will not fail. Not one Mexican who has been denied his consular rights (in the United States) will be executed," Derbez said during a news conference.

The International Court of Justice, the United Nation's highest legal authority, will hear arguments from lawyers representing both countries next week. The Hague, Netherlands,-based body, also known as the world court, has no power to enforce its decisions. The United States has disregarded them in the past.

In 2001, German citizen Walter LaGrand was executed in Arizona, despite the court's order to postpone his punishment until it had heard Germany's case that he had been denied his right to consular assistance.

Representing the U.S. government in next week's hearings are 16 State Department lawyers headed by William Taft IV, greatgrandson of U.S. president William Taft. Mexican newspapers have dubbed the U.S. lawyers the "Dream Team" and emphasized they outnumber Mexico's team of five attorneys by more than three to one.

But Derbez said the difference in numbers will not affect the outcome of the case.

"It is not the quantity but the quality of the lawyers that counts," he said. "And we have right on our side." In February, the world court ruled that the United States must stay the executions of three Mexican citizens on death row in Texas and Oklahoma. Of the 54 Mexicans on death row in the United States, the three were the only ones scheduled to be executed before a decision could be made in the case.