By Ignacio Alvarado
CIUDAD JUAREZ, July 24 (Reuters) - A group of hitmen armed with automatic weapons ambushed the head of a giant prison in a northern Mexican city on Thursday soon after he received threats on his life from suspected drug gangs, said police.
Salvador Barreno, 66, was leaving work at the largest jail in Ciudad Juarez when a group of men with assault rifles chased down his car, killing him and a bodyguard who was driving.
The car was riddled with more than 80 bullet holes, according to local media. Barreno made it to a hospital but died in surgery. His bodyguard was killed instantly.
The prison director had been receiving threats, likely from powerful drug cartels, before his murder, police said.
Last week Alberto Varela, the head of security at the same prison, was killed in a similar attack after his name appeared on a death list pinned on police offices in May.
Drug gangs have hung banners with the names of dozens of policemen around the city near the U.S.-Mexico border this year and have made good on some of their threats, murdering more than 10 of the officers picked out.
President Felipe Calderon has deployed 25,000 troops and federal police to quell the drug war across Mexico, making big narcotics seizures and arresting drug kingpins.
But violence continues to rise as drug gangs fight each other while also targeting troops and police officers.
Gangland killings have surged in Mexico in recent weeks and some 1,800 people have been killed in drug violence this year, some 600 people in Ciudad Juarez alone.
Police are paying a high price, with over 500 killed since Calderon took office in December 2006.
More than 3,000 prisoners are housed in the jail Barreno ran, known for violent riots, with different gangs -- inside and out -- fighting for control of the prison drug trade. (Writing by Mica Rosenberg; editing by Todd Eastham)