Forty-two people have been killed when a boat carrying Somali refugees off the coast of Yemen was fired at from a helicopter, the International Organisation for Migration says.

Women and children were among those killed when the vessel was hit near the Bab al-Mandeb strait, the IOM said.

Images from the scene showed a boat strewn with bodies.

In a separate incident on Friday, at least 22 people died in an attack on a mosque inside a military base in Yemen.

Two missiles were fired at the mosque, in the Kofal military camp west of Marib, officials said.

Boat attack

Among the dead on the boat were Somali refugees carrying identity documents issued by UNHCR, the UN's refugee agency.

About 80 survivors were rescued and taken to hospital, according to the IOM. It is also not known where the boat was travelling to and from.

It remains unclear who carried out the attack. A Yemeni trafficker who survived the attack told the Associated Press that the boat was fired at by a helicopter gunship and a military vessel.

Saudi Arabia, which is leading a US-backed coalition in the war in Yemen, has US-built Apache helicopter gunships. The coalition, which in general controls Yemen's airspace, has not commented on the incident.

A port official told AFP that dozens of Somalis who survived, as well as three Yemeni traffickers, were taken to the city's prison.

Eric Christopher Wyss, of the International Committee of the Red Cross, described the scene at the port as "gruesome and heartbreaking".

"I saw many men, women and children either killed or horribly wounded," he said. "Survivors told us that many of the passengers were refugees from Somalia or Yemen, fleeing conflict."

Despite a humanitarian crisis which has brought Yemen to the brink of famine, migrants from Africa continue to travel to the war-torn country.

UNHCR officials said the people in the boat may have been heading towards Sudan or other countries to the north to escape deteriorating conditions in Yemen.

Somalia is also currently at risk of famine, according to the UN, with 2.9m facing food insecurity - following decades of civil war and a previous famine in 2011.