Hundreds of people have fled their homes in southern Mexico as rival cartels fight for control of routes used to smuggle drugs and migrants.
Locals described cowering in their homes while bullets flew through their homes during a seven-hour gun fight.
More than 700 residents had been displaced from their communities near the Guatemala border, an official said.
The Jalisco New Generation cartel (CJNG) is trying to wrest the area from the grip of the Sinaloa cartel.
Criminal organisations like the CJNG and the Sinaloa cartel have been infiltrating the region because of its proximity to the border with Guatemala and important transit routes for migrants, whom they extort.
The worst-hit communities are Chicomuselo and La Concordia in Chiapas state. Residents of Chicomuselo said 20 people – 18 gang members and two locals – were killed in a cartel battle on 4 January.
In a statement, the community described “the pain at seeing children and youths trembling in fear and getting sick from having to live through these traumatic experiences”. They also accused the state of failing to protect them.
However, the Chiapas state prosecutor’s office released a statement five days later saying that it had not received any reports of any killings in the area.
The military has been deployed to the region but locals say they are now getting caught in the crossfire when the security forces confront the cartels.
Entire families have left their homes and crossed the nearby Angostura lake by boat to escape the violence over the past days.
Local journalists said that their villages now resembled ghost towns.
Chiapas civil protection official Luis Manuel García Moreno told Radio Fórmula that 701 people had fled to the city of Comitán, most of them women and children.