The Mexican government pledged Sunday to probe the killings of a U.S. consulate employee and two family members of consulate staff in a drug-plagued metropolis across from the Texas border city of El Paso.

The Mexican government and officials in the border state of Chihuahua confirmed the shooting deaths Saturday of a Mexican woman who worked at the U.S. consulate in Ciudad Juarez, along with her husband, a U.S. citizen. The husband of another Mexican national who worked for the consulate also was killed in a separate shooting Saturday.

“On the basis of our sustained bilateral cooperation, Mexican law enforcement agencies will work closely with their United States counterparts to track down those responsible of these killings, so justice can be served,” said Ricardo Alday, a spokesman for the Mexican Embassy in Washington.

Mike Hammer, a spokesman for the White House National Security Council, said, “We will continue to work with Mexican President Felipe Calderon and his government to break the power of the drug trafficking organizations that operate in Mexico and far too often target and kill the innocent.”

There were no initial reports as to why the three were killed, but statements from the Mexican government and the White House suggested drug traffickers in Ciudad Juarez, one of the most violent and dangerous cities on the planet, were to blame.

Traffickers are suspected because of recent threats made against consulate personnel, said an official familiar with the matter who refused to be named because of its sensitive nature.

The U.S. Drug Enforcement Administration has given Mexican President Felipe Calderon high marks for cracking down on violent trafficking organizations and arresting many top leaders.

The U.S. Embassy in Mexico late last month denied published reports the DEA would begin embedding agents in Mexican anti-drug units in Ciudad Juarez, where scores of people are murdered every weekend as unabated drug violence increasingly spills across the 2,000-mile U.S.-Mexico border.

The violence isn’t limited to the border. On Saturday, 13 people were killed in the Pacific resort city of Acapulco. Drug traffickers are thought to be responsible for those killings, too.