Prosecutor Tomas Coranado says the remains were discovered stuffed inside two vans near Lake Chapala Wednesday, not far from the city of Guadalajara.
Police say a handwritten note believed to be from the Zetas drug gang was found at the scene.
A woman allegedly linked to the Zetas gang is reported to have told investigators the killings were in retaliation for the murders of 23 people last Friday. The victims were found hanging from a bridge and stuffed in trash bags in the border city of Nuevo Laredo..
The Zetas and Sinaloa drug cartels have a history of violent attacks against one another in battles over turf.
More than 50,000 people have been killed since President Felipe Calderon's crackdown on drug cartels began in 2006.
Some information for this report was provided by AP, AFP and Reuters.