Some 180 young Ethiopian and Somali migrants and refugees, many weakened by hunger and drought in their home countries, were forced from a boat into rough seas off Yemen by smugglers on Thursday, and 19 were presumed to have drowned, the UN migration agency said.
The International Organization for Migration (IOM) had earlier estimated the death toll higher, at 55.
"Staff from IOM... found six bodies on the beach – two male and four female. An additional 13 Ethiopian migrants are still missing (unaccounted for)," the IOM statement said.
Second incident in two days
It was the second such incident in as many days off Shabwa province in southern Yemen, where 50 teenage Africans were "deliberately drowned" on Wednesday by a smuggler who forced 120 passengers off his boat, the IOM said.
Smugglers were pushing migrants and refugees into the sea away from the mainland so as to avoid encountering possibly armed groups on shore in the war-torn country. They were then going back to pick up more migrants.
"It may be the start of a new trend, smugglers know the situation is dangerous for them and they could be shot at, so they drop them near the shore and turn around and get more," IOM spokeswoman Olivia Headon said.
"These people are really thin. There is an ongoing drought situation in Somalia and Ethiopia. Some may not have had much strength to make it alive to the shore," she added.
Thousands taking the perilous journey
Already this year 55,000 people have taken the hazardous route from the Horn of Africa to Yemen to seek possible opportunities offered in the Gulf, IOM said.
Yemen itself is riven by an ongoing war in which forces loyal to the Saudi-backed government are pitted against Iranian-backed Houthi rebels.
Rescue operations and policing at sea to clamp down on the situation are extremely limited in the region, IOM Yemen Chief of Mission Laurent de Boeck said.