Investigators have identified the 12 dead bodies found earlier on Tuesday alongside a road in Mexico's western Michoacan state as federal police officers.
Monte Alejandro Rubido, spokesman for the National Security Council, called the brutal killings a revenge attack by the drug cartel La Familia Michoacana.
The victims, 11 men and one woman, were each killed by a gunshot to the neck.
The police officers, who belonged to a special squad investigating drug crime in the western Mexican state, were apparently led into an ambush by an armed group led by Francisco Javier Farias Lara.
The bodies were abandoned alongside a road.
Rubido said the killings appeared to have been a revenge attack for the weekend arrest of Arnoldo Rueda Medina, a high-ranking member of the gang and the "coordinator of the coordinators."
Mexico has become the epicentre of Latin America's drug trade into the US, with heavily armed gangs battling over the lucrative trafficking of narcotics. Over 3,000 drug-related killings have taken place since January 2009.