At least 52 Somalis died off the coast of Yemen after the ship smuggling them broke down and they were left adrift for 18 days without food or water, the United Nations refugee agency UNHCR said on Sunday.

Rescuers saved 71 people, aged between two to 40, when the ship drifted into Yemeni waters, Geneva-based UNHCR said in a statement. They had paid up to $100 each for the voyage to the Arabian Peninsula country.

"The knife-wielding crew of the smuggling boat told passengers they would travel to the Somali city of Bossaso in a smaller boat to re-charge a battery and then return as soon as possible. They never returned, leaving the passengers adrift for 18 days without food or water," it said.

More than 31,000 African migrants have arrived in Yemen this year, but another 500 have died or gone missing trying to make the journey from Africa, the UNHCR said.

Migrants fleeing war and poverty in Somalia and nearby countries see Yemen as a gateway to wealthier parts of the Middle East, and the West.