This week, Mexican immigration authorities discovered several hundred migrants abandoned in a trailer.

The trailer was left on a highway in Veracruz, a coastal state on the Gulf of Mexico. Inside, agents with the national immigration institute found 343 migrants from Guatemala, Honduras, El Salvador and Ecuador. Among them were more than 100 unaccompanied children, most from Guatemala, according to a release from immigration authorities.

The trailer was equipped with fans and vents, but there have been high profile cases of migrants suffocating in similar situations. Last summer, more than 50 died after a trailer was abandoned on the outskirts of San Antonio, Texas.