Mexican security forces and a local gang engaged in a fierce gun battle in the state of Michoacan on Friday, leaving an estimated 43 people dead, the BBC reported.
Friday's carnage ensued when police responded to an emergency call reporting an invasion of a 277-acre ranch in Tanhuato, near the Jalisco state border.
Government forces have spent years fighting the powerful Jalisco New Generation gang, which controls the local drug trade.
Most of those killed in the three-hour shootout were gang members, but prosecutors said 15 police officers had also been killed, according to the BBC. Authorities said a number of weapons had been recovered from the scene, including dozens of rifles.
The Mexican government has declared a heavy crackdown on the Jalisco New Generation gang, whose members shot down an army helicopter a few weeks ago, killing six soldiers.
At the time, the country's National Security Commissioner, Monte Alejandro Rubido, said the attackers would be brought to justice.
"The full force of the Mexican state will be felt in the state of Jalisco," Rubido said on May 4. "Satisfactory results will start to be seen very soon."
President Enrique Peña Nieto has gone on the offensive against Mexico's main drug cartels since 43 students disappeared last September in the southern city of Iguala.
On February 27, Servando Gómez Martínez, nicknamed "El Profe", was captured by federal police. Martínez used to be a school teacher before becoming the leader of the Knights Templar, one of Mexico's most feared drug cartels.
A week later, Martínez's main rival Omar Treviño Morales, the leader of the Zetas cartel, was also arrested.
During Peña Nieto's 27 months in power a dozen leaders of drug cartels have been captured. Cracking down on the leadership of these criminal organizations has done little to stop urban violence and the flow of drugs, however.
Last week, the leader of a vigilante group set up to drive out the Kights Templar out of Michoacan state was murdered.
In April, 15 army soldiers were killed in an ambush in Jalisco state.