MONTERREY, Mexico - Gunmen killed the top intelligence officer of northern Nuevo Leon state and then torched his car in one of the boldest attacks on security officials in a region where drug-gang violence has besieged Mexico's wealthiest city.

Firefighters arrive to extinguish an armored SUV set ablaze by gunmen in Monterrey Feb 13, 2011. Suspected drug hitmen killed a senior police chief in one of the most brazen attacks yet in Monterrey, Mexico's richest city, El Norte daily reported.[Photo/Agencies]

Homero Salcido Trevino's body was found in a smoldering car abandoned in downtown Monterrey, the state government said in a statement Monday.

Salcido Trevino was the director of the state's intelligence and security center, a job he had taken in August. He was shot at least five times, said the statement, which offered no additional details.

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The attack had some of the hallmarks of a drug cartel hit, but Nuevo Leon Gov. Rodrigo Medina said investigators had not confirmed that. "It is still premature to tell you it was organized crime," he said.

Monterrey, the once-peaceful industrial capital of Nuevo Leon and Mexico's third-largest city, has been traumatized by battles between the Gulf drug cartel and a gang of its former enforcers known as the Zetas.

Gang members have fiercely attacked police and soldiers trying to restore order across Nuevo Leon and Tamaulipas state. Police, mayors -- and even the leading gubernatorial candidate in Tamaulipas -- have been assassinated in more than a year of violence.

Killings soared in Nuevo Leon state last year to 620, compared to 112 in 2009.

"What is evident is that we have a vicious fight between the cartels of organized crime, which have provoked this violence and has obligated us to redouble our efforts," Medina said.

Medina said security officials know the risks they face. He vowed attacks will not "force us to back down or stand aside in this fight."

Local news media reported that Salcido Trevino, who was the nephew of former state Public Safety Secretary Luis Carlos Trevino Berchelmann, had been kidnapped hours earlier as he left his home. Authorities would not comment on the reports.

Nationwide, almost 35,000 people have been killed in drug violence since President Felipe Calderon launched a military crackdown against drug trafficking shortly after taking office in December 2006.

In the Pacific coast resort city of Acapulco, police discovered three dead men from a car left in the parking lot of a state prison Sunday, authorities said Monday. A fourth man was found alive in the car with bullet wounds in the face and neck, Guerrero state police said.

A dozen people were killed in Acapulco over the weekend, including a prison guard, authorities said.