Sana'a, Yemen- Six African migrants drowned and 11 were reported missing and presumed dead after traffickers forced passengers overboard a boat in deep water off Yemen's south-eastern coast, the United Nations refugee agency reported Tuesday.

The boat was carrying 52 passengers - 40 Somalis and 12 Ethiopians - across the Gulf of Aden, the UN High Commissioner for Refugees (UNHCR) said in a statement.

Yemeni authorities recovered six bodies near Huseysa, about 500 kilometres east of the southern port city of Aden, according to the statement.

The boat was one of seven boats carrying migrants that reached the Yemeni coast on Friday after making the perilous voyage from the Horn of Africa.

Survivors reported that the boat departed on Thursday from Suweto, in northern Somalia's Bossasso region.

When the smugglers noticed the presence of Yemeni police onshore, they refused to get closer to the coast and forced passengers overboard in deep water, the UN agency said.

Initial reports said 35 people reached shore near Huseysa, it added.

Since the beginning of the year, 168 boats carrying 9,449 people have reached the Yemeni coast. At least 47 people died while trying to reach Yemen by sea from Somalia during the same period, according to UNHCR.

The influx of new arrivals across the Gulf of Aden since the beginning of this year is slightly higher than during the same period in 2008.

"We are concerned that this trend might continue through 2009," the UNCHR said in its statement.

Many African migrants, mostly from conflict-torn Somalia, try to reach Yemen, which is seen as a gateway to Europe and the oil-rich countries of the Arabian peninsula.

Hundreds of people perish every year in the perilous exodus that takes thousands of desperate Somalis and Ethiopians to Yemen in small boats run by people traffickers operating from Somali ports.

More than 50,000 migrants, the vast majority of them Somalis, resorted to traffickers for the treacherous sea crossing between Somalia and Yemen in 2008.

At least 590 people drowned and another 359 were reported missing last year as result of crossings gone wrong, often with traffickers forcing the migrants overboard, UNHCR said. (dpa)