The United Nations refugee agency UNHCR said at least 22 people died when a smuggler's boat carrying Ethiopians and Somalis capsized off the coast of Yemen on Saturday.
In a statement issued on Monday, the UN agency said another 28 passengers aboard the vessel are missing.
"The smugglers' boat carrying some 120 Ethiopians and Somalis capsized off the coast of Yemen, leaving at least 22 people dead and 28 others missing, according to survivors, Yemeni authorities and the UN refugee agency," said the statement.
It was the second such mishap in the Gulf of Aden in a week, it added.
The boat had set sail from a village near the Somali town of Bossaso -- a major departure point for African migrant smugglers crossing the Gulf of Aden.
Forty-three Ethiopians and two crew members have been detained by Yemeni authorities because they do not have refugee status.
"Yemeni authorities detained 43 Ethiopians -- who do not get automatic refugee status -- from the vessel. But survivors said another 22 Ethiopians had managed to escape. Two of the boat's crew members were arrested by police, while three escaped," the UNHCR said.
But the UNHCR said it has requested Yemeni authorities to grant it access to those detained so it can screen them to see if they are in need of international protection.
"Sunday evening, UNHCR received sketchy reports of the arrival of yet another group of desperate boat people who said they had been forced overboard off the coast of Yemen. Initial reports indicated more casualties were likely," it said.
Thousands of Somalis and Ethiopians try to reach Yemen each year in a bid to escape their home countries' poverty.
On January 16, a boat carrying 65 people reached Yemen after drifting for six days in the gulf with little food or water. Survivors said 20 people, including 16 Somalis and four Ethiopians, died.
Last September, UNHCR called for international action to stem the flow of people falling prey to smugglers after at least 150 boat people died in a three-week period.
The refugee agency said it has been working with local authorities in northeastern Somalia's Puntland region on ways to inform people about the dangers of using smugglers to cross the Gulf of Aden.
There are currently more than 80,000 registered refugees in Yemen, including 75,000 Somalis.
But it is estimated that there are hundreds of thousands more in the country with many of those arriving by sea continue north from Yemen in search of a better life elsewhere.