Four human skulls were discovered inside a package at a Mexican airport that was headed to the United States by courier.
A National Guard statement said the skulls were found wrapped in foil inside a cardboard box after being detected by X-ray equipment at Queretaro Intercontinental Airport in the center Mexico.
He added that the package was sent from the western coastal state of Michoacan and was en route to an address in Manning, South Carolina.
The National Guard gave no further details on the age, identity or possible motive for sending the human remains.
The transfer of human remains requires a special permit from a competent health authority, which has not been obtained, he said.
Michoacan is one of the most violent states in Mexico, with the town of Apatzingan having long been dominated by the Viagras drug cartel.
The Guardia Nacional wrote on Facebook: “During inspections at packaging companies and through an x-ray team, the #NationalGuardia has detected at the intercontinental airport of #Querétaro, four skulls apparently of origin human, wrapped in clear plastic and minio aluminum foil, no health record.”