EL PASO, Texas (Border Report) – The president of Mexico says his security forces will protect residents near the Guatemala border coping with rival gangs vying for control of drug and migrant trafficking.

The comments come a day after authorities in Chiapas confirmed they found 19 bodies in and around a dump truck on a road in the town of La Concordia. State authorities said at least seven of the victims were Guatemalan nationals.

Local media published photos of victims on top of each other in the back of the truck. Some wore military-style garb and boots. A few assault-style rifles are seen next to bodies. Members of the Sinaloa cartel claimed responsibility for the massacre on social media.

It was a regrettable confrontation in Chiapas, on the border with Guatemala, between two rival groups. This has been going on for some time. We will protect the people of the region, President Andres Manuel Lopez Obrador said at a news conference broadcast on YouTube.

This is the fourth time this year mass killings have taken place in La Concordia, 35 miles west of the Guatemalan border. Four severed human heads were left inside a cooler in the parking lot of a convenience store in January. A family of five was shot dead in April, and five of the alleged perpetrators were killed the next day in a confrontation with security forces.

What is motivating this? Drug trafficking and also migrant trafficking. (The region) is a pass, Lopez Obrador said. Regrettably, people from Guatemala were killed. They (the victims) are Mexicans and also Guatemalan brothers. We are looking into this.

U.S. security experts attribute the violence in Chiapas to groups affiliated with either the Sinaloa cartel or the Jalisco New Generation Cartel (CJNG). The Chapos faction of Sinaloa has extensive drug connections in Central and South America with the product passing through Chiapas. A Jalisco-backed group calling itself Cartel de Chiapas y Guatemala (CCYG) has recruited locals and Guatemalans to contest drug and migrant routes.