After an initial decline during the first two years of Enrique Peña Nieto's presidency, killings have roared back to levels that are comparable with those during the worst years of the country's drug war. Violence has been fueled by fractures within long-dominant drug cartels, the growing demand for heroin and other opiates across the border in the United States, and the widespread corruption within Mexican government and security forces, which allow lawlessness to flourish.
Chihuahua has a long history of drug-war violence, including in Ciudad Juarez, the border town that came to symbolize the savagery of the violence.
The former governor of the state fled last year to El Paso and is wanted on corruption charges.
The Wednesday clash occurred after 5:00 am in a village called Las Varas, in the municipality of Madera, between a drug gang known as La Linea and another from the state of Sinaloa, González said.
In recent years, La Linea was allied with the Juarez cartel, which battled Joaquín "El Chapo" Guzmán's Sinaloa cartel for control over Ciudad Juarez. Since Guzmán's extradition to New York this year, security experts have noted significant clashes within and among cartels as they jostle for supremacy.