The planned execution this week of a man convicted in one of Houston's most brutal murder cases in a generation has become among the most contentious in the state that has the nation's busiest capital punishment system.

International attention has been focused on the execution of convicted killer Jose Medellin scheduled for Tuesday. The International Court of Justice, also known as the World Court, said the Mexican-born Medellin and some 50 other Mexicans on death row around the nation should have new hearings in U.S. courts to determine whether a 1963 treaty was violated during their arrests.

Medellin, now 33, is the first among the 50 who is set to die.

His attorneys contend Medellin was denied the protections of the Vienna Convention, which calls for people arrested to have access to their home country's consular officials. He has been in the United States since the age of 3.

"The United States' word should not be so carelessly broken, nor its standing in the international community so needlessly compromised," Medellin's attorneys said, seeking a reprieve in a filing late last week with the U.S. Supreme Court. The high court had not issued any ruling as of Sunday.

President Bush has asked states to review the cases. Texas has refused to budge.

The U.S. Embassy in Mexico warned of possible protests there Tuesday.

Medellin's lawyers went to the Supreme Court after the Texas Court of Criminal Appeals, the state's highest criminal court, refused to stop the lethal injection. The justices ruled in March that neither the President nor the international court can force Texas' hand.