Washington (CNN) -- Federal officials announced Wednesday the formation of a joint task force to investigate Tuesday's shootings in Mexico of two U.S. immigration agents, one of whom was killed.

The announcement came after Homeland Security Secretary Janet Napolitano met with Attorney General Eric Holder to discuss the attack on the two U.S. Immigration and Customs Enforcement special agents.

The FBI will lead the task force, composed of Justice and Homeland Security investigators.

"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 a news release.

"The murder of Special Agent Jaime Zapata and the shooting of another ICE agent provide a sad reminder of the dangers American law enforcement officers face every day," Holder said in the release. "Working with our Mexican counterparts, we have already launched an aggressive investigation, and this joint task force will ensure that every available resource is used to bring the perpetrators of this terrible crime to justice."

Zapata died from his wounds; the second agent was shot in the leg and has been discharged from the hospital in the United States where he had been taken, the release said. Earlier, DHS had said he was shot in the arm and leg.

The attack occurred in the north-central state of San Luis Potosi. as the U.S. agents were driving between Mexico City and Monterrey.

The agents were traveling on a well-traveled highway in an armored car with diplomatic plates on a well-traveled highway, an ICE official said. The official spoke to CNN on condition of anonymity because the case is under investigation.

The agents were returning to Mexico City after meeting other U.S. personnel in the state of San Luis Potosí, ICE said Wednesday in a news release.

"Such meetings among U.S. law enforcement personnel working in Mexico are a regular part of ICE's bilateral cooperation in Mexico under existing agreements," it said, adding that the Mexican government does not authorize U.S. law enforcement personnel to carry weapons.

In a telephone call Wednesday with Mexican Interior Minister Fernando Blake Mora, Napolitano said that violence against DHS personnel in Mexico will not be tolerated, the release said.

The Mexican federal attorney general's office dispatched investigators from its anti-organized crime division to the the state.

President Barack Obama called Zapata's parents Wednesday to express his condolences, White House spokesman Nick Shapiro said.

Senator Joseph Lieberman, I-Connecticut, chairman of the chamber's Homeland Security and Governmental Affairs Committee, called the shootings "the latest reminder of the grievous violence south of our border that must be stopped."

One official said the victims were the first ICE agents to be gunned down in Mexico. According to ICE, the agency has about 30 officers assigned to its office in Mexico City; they work on a range of issues including drugs, weapons, currency and immigration.

Mexican officials also condemned the shootings.

Zapata joined ICE in 2006 and was assigned to a Laredo, Texas, office, where he served on the Human Smuggling and Trafficking Unit and the Border Enforcement Security Task Force, according to the statement from ICE Director John Morton. Zapata had been assigned to ICE's Attache Office at the U.S. Embassy in Mexico City.

In Washington, U.S. Border Patrol Chief Michael J. Fisher said the killing drives home the point that agents have to be prepared for all sorts of threats. "We have to be constantly vigilant in our surroundings and how we deploy and make sure the Border Patrol agents, in particular, that are working in remote areas and sometimes alone are trained the best, which I think they are; that they are equipped the best, which we will continue to do, so they can meet those threats and be able to respond accordingly. Because, quite frankly, that's our mission. The American people deserve no less."

CNN's Jeanne Meserve, Paul Vercammen and Mike Ahlers contributed to this report