At least 12 people were killed in a confrontation between police and armed civilians in the town of El Salto, in west Mexico's Jalisco state, state Governor Enrique Alfaro confirmed.
Four police officers were among the fatal victims, Alfaro said on Thursday through Twitter.
"El Salto police and state police shot down eight criminals yesterday and left three seriously injured, after responding to a report of a safe house where there were hidden weapons," he added.
"Unfortunately, four police officers from the town of El Salto were killed in the line of duty," the Governor said.
In March, the Ministry of National Defense (Sedena) deployed a group of soldiers to violence-ridden Jalisco as part of the Mexico Joint Task Force program to strengthen surveillance of criminal activity in the state in the wake of a wave of killings, Xinhua news agency reported.
The Jalisco New Generation Cartel emerged in 2010 as a cell of the Sinaloa Cartel and now has a presence in at least seven Mexican states, as well as Mexico City.
