Agents deactivated the device and removed most of the explosive material to analyze it before safely detonating the vehicle, thedepartment said. There were no injuries.

Juarez is the same city where drug traffickers staged the first successful car bombing in Mexico, killing three people in July.

There have been three other vehicle explosions in recent weeks in Ciudad Victoria, capital of the border state of Tamaulipas.

Ciudad, across from El Paso, Texas, has been one of the cities most affected by Mexico's drug violence. More than 2,100 people have been murdered there so far this year — putting it on pace to surpass its previous high of 2,700, set last year.

Across the country, more than 28,000 people have been killed since December 2006, when President Felipe Calderon launched a military offensive against the cartels soon after taking office.

In the central state of Morelos, police discovered nine bodies in clandestine graves Saturday in the same area where four more were recently found.

The Public Safety Department said in a separate statement that all 13 victims were believed to have been killed on the orders of U.S.-born Edgar "La Barbie" Valdez Villarreal, one of the alleged kingpins fighting for control of Morelos.

Valdez was captured Aug. 30 by federal police.