The bodies of 34 people, 20 of them children, were found in the desert in Niger.
Government officials said they believed the victims were migrants traveling north in hopes of reaching Algeria or Europe.
Niger's interior ministry announced the discovery Wednesday. A statement on national television said the nine women, five men and 20 children apparently died of thirst after being abandoned in the desert by human traffickers.
Nationalities of the victims have not yet been determined.
The International Organization for Migration said migration from sub-Saharan Africa toward Europe has "substantially increased" in West and Central Africa in recent years.
The migration is mainly linked to employment, but unaccompanied children also are commonly seen traveling the south-to-north route, the IOM added.