At least 31 Somali refugees have been killed in an air strike off the coasts of Yemen, in the Red Sea. The refugees were travelling by boat from war-torn Yemen to Sudan, when an Apache helicopter attacked them, a coastguard in the Hudaydah area told Reuters.

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He added the refugees were carrying official documents from the UN refugee agency (UNHCR).

It is believed at least 80 refugees had been rescued after the incident, which occurred near the Bab-el-Mandeb strait late on Thursday (16 March).

It is not clear yet who is behind the attack. The Hudaydah area, controlled by Houthi forces, has already been the target of air strikes carried out by a coalition led by Saudi Arabia.

Yemen has been ravaged by a civil war which erupted in 2015. The conflict has pitted Iran-allied Houthi forces – who control the capital Sana'a and are allied with loyalists of former president Ali Abdullah Saleh – against forces allied to the government of Abdrabbuh Mansur Hadi, based in Aden, supported by the Saudi coalition.

Both warring sides claim they constitute the government of the country. At least 10,000 people have been killed in the fighting.

Yemen is among the countries at risk of famine. At least 12 million people are facing hunger in the country. Nearly 3.3 million people – including 2.1 million children – are acutely malnourished.