Mexican authorities found 12 decapitated bodies on the Yucatan Peninsula Thursday, but have yet to find the heads, AFP reported.

Photos of the crime scene showed 11 headless corpses stacked on top of one another in a field outside the city of Merida, the capital of Yucatan state. Some of the bodies had tattoos and were jumbled amid blankets and tarps. One was completely naked, while the others wore denim clothing, AFP reported.

A twelfth body was found in a town called Buctzotz, 45 miles northeast of Merida.

It appeared to be the largest single group of beheadings in recent years in Mexico. The tactic has become more frequent in gangland-style killings, and the largest previous instance of decapitations occurred in 2006, when gunmen tossed five human heads into a bar in central Mexico.

"We believe that the 12 executions were an isolated incident and not part of a strategy to destabilize the state," Yucatan state prosecutor Jose Guzman told reporters.

The federal attorney general's office confirmed there were 12 dead and it was taking over the investigation — a move that usually indicates a case involves high-caliber weapons or drug trafficking, both federal offenses.

Merida had largely been spared the drug-gang violence afflicting many other Mexican cities.

Click here to read the AFP report.

The Associated Press contributed to this report.