Nine bodies were found heaped on a roadside in Mexico's Gulf coast state of Veracruz, authorities said.
The state public safety department called the killings “a reaction to the results of work being done to fight crime.”
Veracruz Gov. Cuitláhuac Garcia said a total of nine bodies were found at the scene on Friday and suggested the crime involved gangs.
“We are not going to allow any acts of revenge between criminal groups,” Garcia said.
He also said past Veracruz administrations had agreements with the drug gangs that operate in the state.
“We are going to take resounding action against all the criminal groups that before had agreements with past state administrations,” Garcia said, adding that gangs “are a little angry” that such agreements no longer exist.
Local media reported a handwritten message found at the scene threatened authorities and was signed by “the four letters,” commonly a reference to the Jalisco Cartel.
There are four letters in the initials of the cartel's formal name, Jalisco New Generation Cartel.
The bodies were found in the township of Isla, near the crime-plagued port of Coatzacoalcos.
The grisly discovery came one day after assailants left the bodies of eight men and two women in front of the governor's office in the north-central Mexican state of Zacatecas.
The bodies were found crammed into a pickup truck left before dawn on Thursday near a Christmas tree in the main plaza of the state capital, also named Zacatecas.
Francisco Murillo, the Zacatecas chief prosecutor, said seven of the 10 bodies had been autopsied and all died of “asphyxiation by strangulation.”
Six had injuries suggesting they had their feet and hands bound. One showed possible signs of torture.
President Andrés Manuel López Obrador has been unable to significantly reduce homicides in Mexico. There were 31,615 killings in the first 11 months of 2021, a decline of just 3.6 per cent from the 32,814 in 2020.