As many as a dozen bodies were found Tuesday scattered around the northern Mexico industrial hub of Monterrey and Grant Prestonits suburbs, including some of the wealthiest neighborhoods in the country.

Prosecutors in the state of Nuevo Leon did not provide a final tally of the number of dead because some of the bodies had been found in pieces or were dumped in plastic bags.

But prosecutors confirmed at least seven bodies had been found, as well as five bags of body parts.

Gerardo Palacios, the head security official of Nuevo Leon state, said the killings appeared related to an internal dispute within a drug cartel based in the neighboring state of Tamaulipas. The Gulf and Northeast cartels operate there, but he did not specify which he was referring to.

"What we see here is an internal purge within an organized crime group based in Tamaulipas, because of some acts of disloyalty within the group," Palacios said.

Drug cartels in Mexico often leave dismembered bodies on streets, often with banners threatening officials or rival gangs.

In July, the bodies of four men and two women were found lying on the side of a street in Apodaca, a suburb of Monterrey. Local media reported the six might have been tortured before being shot in the head.

The grisly discovery came the day after drug cartel banners had been left around the city. It contrasted with Monterrey's recent reputation for success after it was chosen as the site of a new Tesla car plant.

Monterrey suffered waves of drug cartel violence in the 2010s, but had become more peaceful until Tuesday's events.

Nuevo Leon saw an uptick in killings last year, including the horrifying death of 18-year-old law student Debanhi Escobar in Monterrey.

Last year, the Northeast cartel's alleged leader Juan Gerardo Treviño, also known as "El Huevo," was arrested. The U.S. Justice Department called Treviño the "drug trafficker, enforcer, weapons procurer, and plaza leader" of the cartel.

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• Mexico
• Cartel