Mexico on Friday returned the bodies of 16 Guatemalan nationals massacred in one of its northern border states, a case that caused renewed consternation about the dangers faced by migrants bound for the United States.

The bodies, some badly charred and with gunshot wounds, were found in January along a migrant smuggling route in a remote area of Tamaulipas state in the municipality of Camargo.

Covered with Guatemalan flags, the coffins arrived in the morning in Guatemala City. Relatives who had traveled in the same plane from Mexico City held photographs of the dead.