Mexican police have found the mutilated bodies of six men inside plastic bags dumped on a road leading to the tourist city of Cuernavaca.

Morelos state prosecutors say the bodies were found Wednesday on a highway in the town of Yautepec along with a threatening message left under a human head. State Attorney General Pedro Benitez tells local media the message was addressed by a drug gang to a rival but has given no other details.

The state of Morelos was formerly under the control of the Beltran Leyva gang, which broke up after its leader was killed by Mexican marines two years ago in Cuernavaca. Fighting among remnants of the gang has caused an upsurge in violence in the small state that neighbors Mexico City.