Authorities have found mass graves with the charred remains of up to 20 people in the restive southern Mexican state of Guerrero, at a time when police are scouring the area for nearly four dozen missing students after a rash of violence.
The remains were buried on a hillside up a rocky dirt track on the outskirts of Iguala in six suspected graves, which were still fresh, a local official said, speaking on condition of anonymity.
Investigators discovered the burned remains, which were put into bags, two officials said, asking to remain anonymous. It was unclear who the remains belonged to, they added.
Guerrero Attorney General Inaky Blanco told reporters in Iguala on Saturday that the remains would be sent to Mexico's forensic service to determine whether or not the corpses match those of the missing students.
He declined to say how many graves or corpses had been found.
The grisly discovery was made just before midday on the northwestern outskirts of Iguala. Local and state police cordoned off the entrance to road leading up a hill where multiple police vehicles had entered.
Blanco, flanked by armed guards, visited the site and said investigators were examining the graves in the heavily guarded area.
"In the next few hours we will determine the cause of death and the number of bodies," a spokesman for the state attorney general's office said.
Iguala is located about 120 miles (193 km) south of Mexico City in the increasingly violent state of Guerrero, the site of clashes involving students, police and armed men last week. At least six people were killed in a spate of incidents.
The state governor said earlier this week that photos showed police had taken some of the students away.
An police official said on Saturday that there is video footage of between eight to 10 students being put into police trucks.
Twenty-two police officers were arrested in Guerrero on Sunday accused of killing two students during the clashes last week.
Guerrero Governor Angel Aguirre said on Saturday that a total of 30 individuals have now been detained in connection with the incidents.
Local government officials criticized the police for showing an excessive use of force with the students in Guerrero, where gangs have evolved from a fragmented drug cartel and are fighting turf wars.
Thirteen of an original group of 57 missing people re-emerged this week. Some had hidden, others had gone home. Dozens are still unaccounted for.
Many mass graves have been found across Mexico in recent years and months, the legacy of drug gang violence that has killed around 100,000 people since 2007.