Families and friends of missing persons have uncovered clandestine mass graves containing 32 bodies and nine human heads in Mexico's violence-plagued southern state of Guerrero.
The remains were unearthed between Tuesday and Thursday in 17 pits on a hill in the village of Pochahuixco, part of the municipality of Zitla, a region beset by turf wars between drug cartels.
"The discoveries are terrible," Guerrero state security spokesman Roberto Alvarez said.
The remains were taken to the state capital, Chilpancingo, to be identified, Mr Alvarez said in a statement. Soldiers are scouring the region for more hidden graves.
Drug cartels have been burying their victims in hidden graves across the country for years, and authorities regularly find human remains.
Guerrero is one of the country's most violent states and a major opium poppy grower, with the Guerreros Unidos and Los Rojos drug gangs engaged in brutal battles to control criminal operations that also include extortion.
Last weekend at least 24 people were killed in the state. The bodies of nine men, including five that were dismembered, were found on a roadside.
Last week a dozen people were abducted in another part of the state that has been hit by a rash of mass kidnappings for ransom.
Guerrero is also known for the disappearance of 43 students in the city of Iguala in September 2014, a case that drew international outrage and remains unsolved.
The Pacific resort of Acapulco, once a famous destination for Hollywood stars, is now considered the country's murder capital as the Beltran Leyva gang and the independent Cartel of Acapulco battle for supremacy.
The Iguala case put a spotlight on the rash of disappearances in Mexico, where some 28,000 people have been reported missing since 2007.
Frustrated by the lack of progress by the authorities, mothers, fathers, brothers and sisters of the disappeared have led their own searches across the country, learning to detect clandestine graves on their own.