Over 3,700 Somali refugees have made the perilous sea journey across the Gulf of Aden to Yemen in August alone amid the severe drought in their homeland, the UN refugees agency said Friday.

"Yemen is seeing a sharp rise in the number of Somali refugees arriving on rickety boats across the Gulf of Aden," said Adrian Edwards, spokesman for the UN High Commissioner for Refugees.

"More than 3,700 Somali refugees have reached Yemen's coast so far in August," said the spokesman.

The number marks a sharp jump from the 15 who crossed the Gulf of Aden for the whole of 2010.

"It is testament to the refugees' desperation that they have chosen to flee to Yemen, which is itself affected by serious unrest," said Edwards.

"The new arrivals tell our staff they fled Somalia because of the unstable security situation, severe drought, high food prices and lack of job opportunities," they said.

In addition, the journey is extremely dangerous, with two Somalis drowning when a boat capsized on Monday.

"Nonetheless, more Somalis are expected to arrive in Yemen in the coming months. We believe that many who fled their homes are already waiting in Bossaso for calmer seas before starting their journey," said Edwards, referring to the staging point in northern Somalia.

But even as the outflow via Yemen increased, the displacements within Somalia or to Kenya were falling.

Arrival rates in Mogadishu dropped to about 200 a day in August, compared to 1,000 a day in July.

The UNHCR said that due to insecurity, almost no movements were recorded in Mogadishu districts previously under control of the Al-Qaeda-linked Shebab militia.

In areas under the control of Shebab rebels, meanwhile, restrictions on movements were being imposed.

In addition, donations as well better access to aid may have led others to head to places where there are relief supplies, rather than to Mogadishu.