MEXICO CITY (AFP) - At least 42 "suspected criminals" were killed on Friday in a gunfight with federal police in a western Mexico region hit by cartel violence, one of the bloodiest clashes in the country's drug war.
One police officer also died in the shootout with armed civilians in the municipality of Tanhuato, in Michoacan state, near the border with Jalisco state, a federal government official told AFP.
The official said the dead included "42 suspected criminals and one federal police officer."
Authorities had earlier reported the deaths of two officers.
Michoacan Governor Salvador Jara said the clash erupted when security forces stopped a suspicious vehicle, prompting its passengers to shoot.
"This was the beginning and then it evolved because the preliminary report I have is that those who were attacking were numerous," Jara told Radio Formula, adding that he could not confirm the death toll.
A federal police commander told AFP that the convoy chased the shooters into a ranch known as El Sol, where the clashes continued. Some 500 federal police and troops were guarding the ranch.
Jara said it was "very probable" that the Jalisco New Generation drug cartel was involved but that the attack was under investigation.
The New Generation cartel has launched deadly ambushes against police this year in Jalisco, but the identity or criminal affiliation of the armed civilians in Friday's clash was not immediately known.
It was unclear how the authorities avoided a death toll as high as the suspects' but an official said the government would give a press conference later on Friday.
Michoacan and Jalisco have endured some of the worst violence in a drug war that began to escalate in 2006, when the government deployed troops to combat cartels.
More than 80,000 people have been killed and another 22,000 gone missing nationwide in the past nine years.
The western region poses one of the toughest security challenges facing President Enrique Pena Nieto since he took office in December 2012.
NEW GENERATION AMBUSHES
Tanhuato is near the border with Jalisco, where the powerful and heavily-armed New Generation gang has been battling security forces.
The municipality is a short drive from the town of La Barca, where 64 bodies were unearthed from mass graves in 2013.
The New Generation cartel has taken the authorities head-on this year, killing seven soldiers and a policewoman when they took down a military helicopter with a rocket-propelled grenade on May 1.
The attack on the helicopter came on the day the government announced Operation Jalisco, a military and police strategy against the New Generation cartel.
In April, the cartel killed 15 state police officers on a highway near the Jalisco village of Soyatan. A month earlier, the gang killed five federal police gendarmes in the town of Ocotlan.
Tanhuato is also near Yurecuaro, a Michoacan town where a former vigilante leader who was running for mayor was shot dead during a campaign event last week.
The Yurecuaro candidate, Enrique Hernandez of the leftist Morena party, was killed by gunmen in a vehicle, while three people were wounded.
Farmers formed vigilante forces in Michoacan in 2013 to drive out the Knights Templar drug cartel, which has been weakened by arrests of its top leaders.
The government last year turned the vigilantes into a "rural defence" force, but the movement has been marred by deadly infighting since then.
In December, 11 people died in a shootout between two self-defence groups.