Masked gunmen set fire to a market in Mexico, killing nine people Monday — with the deadly arson attack coming just days after body parts and drug cartel messages were found in the same city plagued by gang violence.

A group of unknown attackers showed up at the sprawling public market in Toluca, opened fire and then doused the area with a flammable liquid before setting it ablaze and fleeing, prosecutors said.

“Nine people lost their lives, eight of them at the site and one more in a hospital,” read a statement from the State of Mexico’s prosecutor.

Three of the victims appeared to be children under the age of 18, but they have not been identified yet.

Prosecutors were investigating private security guards for abandoning their posts at the time of the shooting and arson attack.

As of Tuesday, no one has claimed responsibility for the carnage in Toluca, a city of nearly a million residents located about 40 miles west of Mexico City.

The statement from state prosecutors said that “one of the first lines of investigation is that events may have been related to internal disputes over the possession of commercial spaces” at the market — the second largest in Mexico boasting 26,000 daily visitors.

Toluca Mayor Raymundo Martinez also told the Milenio newspaper that the fire was possibly the result of squabbles between vendors and property owners.

The deadly market inferno comes less than a week after at least two hacked-up bodies were discovered in Toluca, surrounded by handwritten signs claiming responsibility for the slaughter by the ruthless Familia Michoacana drug cartel.

A severed human leg was spotted hanging from a pedestrian bridge last Wednesday, followed by the discovery of a man’s torso believed to be from the same body in the street below.

Additional remains were later found in another neighborhood in Toluca, also accompanied by cartel signs.

Pieces from a second dismembered body were then discovered on the city’s east side and inside a burning car on the north side. 

The Familia Michoacana originated in the neighboring state of Michoacan in the early 2000s, and while it has been largely chased out of its home state, it has spread into the State of Mexico and Guerrero state.

The cartel has become notorious for ambushing and killing police officers in Mexico State and civilians in Guerrero, where the Familia Michoacana has been waging a bloody turf war with other local gangs.

The cartel “has specialized in methamphetamine production and smuggling, along with other synthetic drugs,” according to the US Justice Department.

Over the weekend, prosecutors in Guerrero said that four taxi drivers were shot to death, with at least one of their cars set on fire, in and around the state capital of Chilpancingo. The killings have been linked to one of the gangs battling the Familia Michoacana.

Chilpancingo was the scene of horrific drug gang violence in late June, when pieces of seven butchered bodies were left on a downtown street, along with a threatening message from a gang.

With Post wires