At least 20 people drowned after smugglers threw dozens of migrants overboard during a crossing between Djibouti and Yemen, the International Organization for Migration (IOM) said Thursday.

"Survivors believe at least 20 people have been killed. There are still some unaccounted for. Five bodies washed up onshore," said Yvonne Ndege, IOM regional spokesperson for the East and Horn of Africa, told AFP.

At least 200 migrants, including children, were aboard the vessel when it left Oulebi in Djibouti in the early hours of Wednesday for Yemen, survivors told the IOM.

About thirty minutes into the voyage across the Gulf of Aden the smugglers panicked, survivors said, throwing around 80 people overboard before turning the vessel back toward Djibouti.

"Of the 80 people who were forced off, only 60 made it back to shore," Ndege said.

Five bodies were recovered Wednesday and there are fears the death toll could still rise. 

The survivors are receiving medical treatment in the Djibouti port town of Obock and testimonies are still being collected.

Two similar incidents in the Gulf of Aden in October claimed the lives of at least 50 migrants, the IOM said.