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The Department of Homeland Security and the Department of Justice are forming a joint task force to find the assailants who killed a U.S. immigration agent and injured another while the two officials were driving in Mexico on Tuesday.

Homeland Security Secretary Janet Napolitano announced the task force in a statement released after her meeting Wednesday with U.S. Attorney General Eric Holder to discuss the incident, which threatened to strain already challenging relations between Mexico and the United States over the growing violence along the U.S.-Mexican border.

"This joint task force reflects our commitment to bring the investigatory and prosecutorial power of the U.S. Government to bear as we work with the Mexican Government to bring these criminals to justice," said Napolitano in the statement.

"Our thoughts and prayers are with the [immigration] agents' families and loved ones, as we are reminded of the risks and sacrifices undertaken every day by the men and women on the front lines in protecting the safety and security of the American people."

Officials say U.S. special agent Jaime Zapata died Tuesday after assailants opened fire on an SUV carrying the agents from Monterrey to Mexico City. Zapata was on assignment from his post in Laredo, Texas.

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U.S. and Mexican officials said they were working together on the investigation.

The FBI will be heading the joint task force, said the statement from Homeland Security, “and will leverage the investigative capabilities of both agencies to work with Mexico in tracking down the perpetrators and swiftly bring them to justice.”

On Wednesday, Texas Gov. Rick Perry called on U.S. and Mexican governments to work together to keep citizens safe and bring justice to the gunmen.

In an interview with The Associated Press, Perry said "nobody's safe as long as these drug cartels are operating."

Perry said "both the American and Mexican federal governments have failed at keeping their citizens safe."

He called on President Barack Obama and President Obama and President Felipe Calderon to work together.

Perry urged Americans to take precautions while traveling to Mexico and renewed his call for more border patrol troops on the border.

President Obama also called Zapata’s parents to offer condolences and told them that that their son served admirably and that the U.S. was grateful for his selfless service, White House spokesman Nick Shapiro said.

Elizabeth.Llorente@FoxNewsLatino.com

This story contains material from The Associated Press.

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