At least 11 people were killed in a shootout between criminal groups in Nayarit on Thursday, state authorities said.

The violence occurred in the municipality of Huajicori, located on Nayarit’s border with Sinaloa and Durango, and was reportedly between members of the Sinaloa Cartel and the Jalisco New Generation Cartel (CJNG).

The Nayarit Security Ministry said in a statement that 11 bodies were found in an area known as “Las Antenas” after “a confrontation between criminal groups” allegedly occurred.

It didn’t say which criminal group, or groups, the victims belonged to.

The newspaper Milenio reported that the discovery of the 11 bullet-ridden bodies was made around 9 a.m. on Thursday while security forces were carrying out patrols in the Sierra de Nayarit, a mountainous area in the northern part of the Pacific coast state.

Authorities also found spent bullet casings and high-caliber weapons.

The Nayarit Security Ministry said that state police, soldiers, National Guard personnel and state investigative agents have “intensified” joint operations in the area to protect the safety of residents.

Milenio reported that the Sierra de Nayarit is known as a “point of conflict between criminal groups.”

Nayarit is located between Sinaloa, the base of the Sinaloa Cartel, and Jalisco, the home of the CJNG. Those criminal organizations are Mexico’s two most powerful and are major exporters of narcotics to the United States.

The newspaper El Financiero reported that there have been frequent confrontations between the Sinaloa Cartel and the CJNG in Huajicori in recent months. Some families have relocated to other parts of the state, El Financiero said, adding that the violence has also affected the local economy and forced schools to close.

Violence related to turf wars between the Sinaloa Cartel and the CJNG has also displaced people in other parts of Mexico, including in the border region of the southern state of Chiapas.

Members of the Sinaloa Cartel are not just fighting operatives of other criminal organizations, but also each other.

A long-running battle between the “Los Mayos” and “Los Chapitos” factions of the Sinaloa Cartel has intensified in Sinaloa in recent weeks after cartel leader Ismael “El Mayo” Zambada was arrested in the United States.

Zambada, a co-founder of the Sinaloa Cartel along with convicted drug lord Joaquín “El Chapo” Guzmán Loera, alleges that he was kidnapped by Joaquín Guzmán López, one of El Chapo’s sons, and forced onto a private plane that delivered him into the hands of U.S. law enforcement authorities.

With reports from Milenio and El Financiero