GENEVA (Reuters) - Roughly 50 teenage Somali and Ethiopian migrants were “deliberately drowned” early on Wednesday by a smuggler who forced 120 passengers into the sea off Yemen’s coast, the International Organization for Migration (IOM) said.

“The survivors told our colleagues on the beach that the smuggler pushed them to the sea, when he saw some ‘authority types’ near the coast,” Laurent de Boeck, the IOM Yemen Chief of Mission, said in a statement.

“They also told us that the smuggler has already returned to Somalia to continue his business and pick up more migrants to bring to Yemen on the same route,” he said.

IOM staff found the bodies of 29 African migrants buried in shallow graves on the beach in Yemen’s southern province of Shabwa along the Gulf of Aden, while another 22 were missing after the tragedy, according to survivors.

“They were all quite young, the average age was around 16,” IOM spokeswoman Olivia Headon said.

IOM officials spoke with 27 survivors who reported that a further 42 people had survived but had already left the beach, she said.

The migrants, who included some young women, had headed to war-torn Yemen in order to seek opportunities in Gulf countries. Already this year 55,000 migrants from the Horn of Africa have taken the hazardous route, IOM said.