Mexican authorities on Saturday sent reinforcements of 1,800 police troops in the fight against drug cartels, after more than 40 people were found dead in three Mexican cities over the past two days as drug gang fighting intensified, local media reported.

The Public Safety office announced that the well-equipped 1,800 federal agents were sent to Michoacan state on Saturday, in a battle there mainly against the Knights Templars, a splinter group of the La Familia drugs cartel.

National Security Council spokesman Alejandro Poire said it was a "reinforcement operation faced with the possibility of greater mobilization by organized crime groups."

Poire reiterated that it were these criminals, not the government's crackdown on organized crime, that has caused waves of drug gang-related violence. More than 35,000 people have died since President Felipe Calderon stepped up the fight against organized crime in 2006, according to official figures.

"The violence won't stop if we stop battling criminals," Poire said. "The violence will diminish as we accelerate our capacity to debilitate the gangs that produce it."

At least 20 people were killed and five injured when gunmen opened fire in a bar late Friday in the northern city of Monterrey, where the Zetas gang is fighting its former ally, the Gulf Cartel, according to Alejandro Poire.

Eleven bodies were found earlier Friday near a water well on the outskirts of Mexico City, where the gang is fighting the Knights Templar, an offshoot of the La Familia gang that has terrorized its home state of Michoacan, said Poire.

Poire added another 10 people were found dead early Saturday in different parts of the northern city of Torreon, where the notorious Zetas are fighting the Sinaloa cartel.