MEXICO CITY (AP) — Authorities in Mexico say four Mexican citizens have died in a climbing accident on the Pico de Orizaba.

Also known by its indigenous name Citlaltepetl, the volcanic peak is the highest in Mexico, at 18,619 feet.

The civil defense office in the central state of Puebla said Sunday that two of the climbers were from the neighboring state of Veracruz and at least one was from Puebla.

The office says all four deaths appear to have been related to a fall.

Photos distributed by the office show rescue workers trying to bring the bodies down from a loose, rocky apron below an even steeper slope above the snow line.