"It may be the start of a new trend, smugglers know the situation is risky for them and they could be shot at, so they drop them near the shore", Olivia Headon, IOM spokesperson, told Reuters on Thursday.
"The smugglers deliberately pushed the migrants into the waters since they feared that they would be arrested by the authorities once they reach the shore", an IOM emergency officer in Aden told AFP.
The IOM estimates some 55 000 migrants have nonetheless left the Horn of Africa for Yemen since the start of 2017, more than half of them under the age of 18. "And they have no choice", de Boeck told the AP. "The smugglers are well aware of what's happening in Yemen, so it may just be they're trying to protect their own neck while putting other people's lives at risk".
After migrants were forced into the seas on Thursday, the migration agency counted five bodies.
A further 22 boat occupants among Wednesday's total of 120 were still missing, the IOM added, describing the practice as "shocking and inhumane".
"They have a choice, of course, and not all decide to return back home".
"These people are really thin".
Ethiopians are also facing acute hunger, with the United Nations saying at least 8.5 million people in the country are in need of immediate food assistance. "Some may not have had much strength to make it alive to the shore", she said.
An IOM statement said its staff had provided urgent care to surviving migrants who had stayed on the beach.
Despite the war in Yemen, almost 55 000 migrants have left the Horn of Africa, to arrive in this country from January 2017, according to IOM. The passengers' average age was around 16, the agency said.
Many others also try to reach Europe via Libya and the Mediterranean Sea.
Yemen's conflict itself is a deadly risk.
The survivors told the migration agency that the smuggler had already "returned to Somalia to continue his business and pick up more refugees to bring to Yemen on the same route".
"The difficulty is also that this is a criminal network which is organised not only in Yemen but also in Somalia, in Djibouti as well as Ethiopia", he said.