MONTERREY, Mexico (Reuters) - Police found five mutilated bodies outside the wealthy city of Monterrey on Tuesday, part of a series of attacks that killed 23 people and dragged the region deeper into Mexico’s drug war.

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Gunmen dumped the five dead men, their arms and legs chopped off, on a street in the town of Montemorelos south of Monterrey just before dawn, police and witnesses said, in a escalation of killings since the New Year blamed on drug cartels and alarming locals and businesses. [nN12146154]

The unprecedented spate of killings over the past 24 hours in and around Monterrey also included the drive-by shooting of three brothers while they were eating tacos, and an attack by gunmen on five men in a working class neighborhood. One woman died of a heart attack after witnessing that multiple homicide, and nine were killed in other shootings, police said.

“In this toll of 23 deaths ... it is clear this violence is being unleashed by warring criminals,” said Jorge Domene, security spokesman for the Nuevo Leon state government. Monterrey is the state’s capital.

DOWNWARD SPIRAL

Drug violence in Monterrey -- once considered a model city where income is double Mexico’s average -- soared to record levels last year and killings have further intensified in the first few weeks of 2011.

At least 60 people have died in drug violence in just 18 days across Nuevo Leon, and gangs are increasingly targeting corrupt police they suspect are working for rivals. The state government is struggling to respond and has called on President Felipe Calderon to send more troops.

“The police don’t have the capacity to patrol the streets. Business people know that they are opening and running their companies at their own risk,” said Juan Ernesto Sandoval, the head of Monterrey’s commerce, retail and tourism chamber.

Mexican and U.S. officials say that in Monterrey, an alliance of three cartels is trying to rid the region of the Zetas gang, which is led by former elite soldiers who switched sides to join organized crime in the 1990s, and take control.

With some 4 million people just 140 miles from the Texas border, Monterrey’s slide into the drug war marks a dramatic unraveling of security in just over a year.

Home to global cement maker Cemex and foreign factories including General Electric, the region generates 8 percent of Mexico’s gross domestic product with just 4 percent of the country’s population. It was known across Latin America as a haven of peace and prosperity.

More than 34,000 people have been killed in drug violence across Mexico since Calderon sent the army to fight the cartels in 2006. The government says the bloodshed is a sign the gangs are weakening, but many Mexicans and rights groups worry the strategy has backfired, sparking a relentless stream of killings that is spilling out across the country.