"They started prodding the people with the barrels of their guns ... and forced them to jump. Many people must have drowned," said Ali Sidow Qaddi, who swam three miles to the Yemeni port of Shabwa, where he was rescued on Saturday.

The traditional dhow carrying 80 passengers left Marer on Somalia's north-east coast last Thursday, heading north across the Gulf of Aden towards Yemen. Two other boats carrying about 200 people also hoping to find work in Yemen left the day before and the day after.

Mr Qaddi said he had paid $50 (£32) for the crossing to Yemen after travelling three weeks by road from southern Somalia.

Hussein Hajji Ahmed Mohamud, the acting Somali consul in Yemen, said survivors had told him they had seen six bodies floating in the water and the authorities had buried seven that had washed ashore.

He said the survivors had been handed over to the United Nations High Commission for Refugees in Yemen.

Hundreds of people have died trying to reach Yemen in in search of jobs since Somalia descended into chaos when rival clan-based factions ousted the dictator Mohamed Siad Barre in 1991, then turned on each other.

In May, more than 80 Somalis and Ethiopians died when their boat broke up in the Gulf of Aden on a similar voyage. A month earlier, 27 people were beaten to death by a boat's crew during a storm.