An official in the Mexican state of Sinaloa says the bodies of 13 people have been found in a rural area.
The official said yesterday that the nine men and four women apparently died of gunshot wounds.
The official was not authorised to be quoted by name under government policy.
The state prosecutor's office is still investigating the identities of the dead and possible motives in the killings.
Authorities found the bodies near the municipality of San Ignacio, close to the border with the neighbouring state of Durango.
The area is among the prime drug-producing regions in Mexico and has been the scene of turf battles between drug gangs.
