Mexico captures suspects in U.S. agent's killing

MEXICO CITY (Reuters) - A Mexican drug gang killed a U.S. customs agent and wounded another last week after mistaking the officials for rivals, Mexican officials said on Wednesday as they presented several captured suspects.

The two U.S. Immigration and Customs Enforcement agents were set upon on a major highway near the central city of San Luis Potosi, north of the capital, in one of the worst attacks on U.S. agents in Mexico in more than a decade and a sign of Mexico's worsening drug war.

Six male prisoners accused in the attack were presented to the media on Wednesday and officials named four other detainees -- three women and a minor.

The attackers spotted the agents driving in a dark sport utility vehicle on February 15 and pursued them before opening fire, Mexican prosecutors said.

"They confused the look of the car and thought the (agents) were working for a rival gang," the prosecutor's office said in a statement.

The suspects are linked to the Zetas drug gang and security forces recovered several rifles and small arms when they made arrests, officials said. U.S. law enforcement is eager to have access to the suspects, an American official said.

President Barrack Obama spoke with Mexican President Felipe Calderon on Wednesday to thank him for Mexico's efforts to bring the attackers to justice.

"The president said neither the United States nor Mexico could tolerate violence against those who serve and protect our citizens," the White House said in a summary of the phone call.

The two unarmed agents were shot after their armored SUV was forced off the road by two vehicles. Agent Jaime Zapata later died of his injuries. More than 1,000 people attended his funeral in south Texas on Tuesday.

Homeland Security Secretary Janet Napolitano praised Mexico for the suspects' arrest, underscoring Washington's strong support for Calderon's crackdown on drug cartels despite a death toll of more than 34,000 since December 2006.

"We will continue to assist the ongoing Mexican investigation with every resource at our disposal and to ensure that all those responsible for Special Agent Zapata's murder face justice," she said..

Escalating violence in oil-producing Mexico, an important U.S. trade partner, has caused alarm in Washington, which is providing $1.3 billion in funding and training for Mexico.

The two countries say cooperation is better than ever and U.S. intelligence is believed to have played a major role in the killing or capture of several top drug bosses.

But in an interview published this week, Calderon lashed out at U.S. intelligence services, saying they were too busy competing with one another to be effective.

Officials had not said which of Mexico's drug cartels may have been behind the latest attack, although many suspected the Zetas cartel, a group led by renegade Mexican soldiers and widely seen as the most brutal of the gangs.

(Additional reporting by Arshad Mohammed and Jeremy Pelofsky in Washington with Patrick Rucker in Mexico; editing by Robin Emmott and Christopher Wilson)