GENEVA - A dozen African would-be migrants died in "horrific circumstances" while attempting to cross the Gulf of Aden from Somalia to Yemen over the past week, the United Nations refugee agency (UNHCR) said on Tuesday.

Four boats carrying more than 300 Ethiopian and Somali migrants have landed on Yemen's coast over the past eight days, at the start of the annual smuggling season, UNHCR spokesman Ron Redmond told a news briefing.

Passengers reported being beaten with clubs and stabbed by the smugglers arranging their voyage, who ask between $60 and $100 for the often-dangerous journey.

At least five migrants were abused and thrown overboard, and another six died of suffocation and dehydration in the crowded, unhygienic hold of the boat they travelled in, Redmond said. An additional person drowned after disembarking in deep waters.

Somali refugees told UNHCR staff in Yemen they were fleeing violence, arbitrary killings, drought and a lack of work in their country. Many also said they were seeking to join relatives and family members in Yemen and in Saudi Arabia.

The International Organisation for Migration (IOM), a Geneva-based aid and advocacy group, said on Tuesday it was seeking funding to provide counselling to asylum-seekers upon arrival in Yemen, and to help educate people in Somalia about the dangers of crossing the Gulf of Aden.

"Very few migrants are aware of the risks involved in this perilous journey, which also includes long treks in the scorching desert, thirst, starvation and various forms of assault by shiftas, or local bandits," IOM spokesman Jean-Philippe Chauzy said.

Some 26,000 migrants and asylum-seekers entered Yemen by sea last year, according to UNHCR figures. Smugglers usually operate in the Gulf of Aden area from September to June.