Soldiers of the Mexican army walk in front of the rugged military helicopter and van in Santiago Jamiltepec, Oaxaca state, Mexico, on February 17, 2018. A 7.2-magnitude earthquake rattled Mexico on Friday, causing little damage but triggering a tragedy when a minister's helicopter crash-landed on the way to the epicenter, Oaxaca, killing two people on the ground. Pic/AFP

A military helicopter carrying officials assessing damage from a powerful earthquake crashed Friday in southern Mexico, killing 13 people and injuring 15, all of them on the ground.