Medellin, 33, was condemned for the 1993 killings of Jennifer Ertman, 14, and Elizabeth Pena, 16, who stumbled into a drunken midnight gang initiation rite at a park in north Houston, the Houston Chronicle said.
Medellin's accomplice, Derrick O'Brien, was executed in July 2006. Also sentenced to die is gang leader Peter Anthony Cantu. Three other accomplices are serving prison sentences.
The U.N. court called for stays of Medellin and four other Mexican nationals awaiting execution in Texas came in response to a petition filed last month by the Mexican government. The request was for time to determine whether denying the men access to the Mexican Consulate after arrest impaired trial defenses, the Chronicle said.
U.S. President George Bush directed state courts to abide by the world court's decision and specifically asked Texas to review the Medellin case.
But, the U.S. Supreme Court ruled that Bush couldn't compel Texas to review the situation without concurrence of the legislative branch.