Smugglers are believed to have "deliberately drowned" scores of teenage migrants off the coast of Yemen.
The International Organisation for Migration (IOM) made a statement on Thursday asserting that 29 shallow graves had been discovered on a beach in Shabwa in the south of the country.
A routine patrol of the beach made the grisly discovery.
The IOM believes a smuggler in charge of a boat forced more than 120 people off the vessel while it was still in transit to Yemen, from where the passengers planned to travel to other Gulf countries.
Up to 50 Somali and Ethiopian migrants are thought to have drowned, and the smuggler is thought to have returned to Somalia to conduct another trip.
An estimated 55,000 people have left the Horn of Africa - the eastern region made up of Somalia, Eritrea, Ethiopia, and Djibouti - to travel to Yemen since January this year.
The motivation is to find more prosperous economic opportunities across the Gulf countries.