At least 70 Ethiopians have drowned after a boat to Yemen sank in the Red Sea. It is believed the boat was being used to transport illegal migrants.

Authorities say the small vessel sank on Saturday due to high winds and rough seas.

Tens of thousands of migrants crowd into boats each year to reach Yemen, which is seen as a gateway to wealthier parts of the Middle East.

The United Nations Refugee Agency (UNHCR) has seen a sharp increase this year in the number of migrants and asylum-seekers losing their lives in attempts to get to Yemen.

In October, 64 migrants and three crew died when their vessel, sailing from Somalia, sank in the Gulf of Aden. Since then, five more deaths bring the yearly tally for 2014 to 215 - exceeding the combined total for 2011, 2012 and 2013 of 179.

The UNHCR found that boats crossing to Yemen are often dangerously overcrowded, and smugglers have reportedly thrown passengers overboard to prevent capsizing or avoid detection.

Search-and-rescue officials say the practice has resulted in hundreds of undocumented casualties in recent years.