An air strike killed at least seven people, including four children, on Wednesday in a rebel-held district of northern Yemen, the Huthi rebels and a medical source said.

The Huthi-run news site Saba reported 12 dead in what the Shiite rebels said was an air raid on Baqem district in the northern province of Saada.

The rebels' Al-Masirah television blamed the attack on a Saudi-led coalition which is fighting alongside Yemen's government in a war that has claimed thousands of lives.

Speaking on condition of anonymity, a medical source in Baqem said seven people -- four children, two women and a man -- had been killed in the raid on Saada, which borders Saudi Arabia.

More than 8,500 people have been killed and millions displaced since the Arab coalition joined the war in 2015 to bolster the government of Abedrabbo Mansour Hadi in its fight against the Iran-backed rebel alliance.

The conflict has pushed 17 million people to the brink of famine in what the United Nations this year called the "largest humanitarian crisis in the world".

Yemen is also facing port and airport blockades and a cholera outbreak that the International Committee of the Red Cross estimates has killed more than 2,100 people since April.

The UN Human Rights Council last week agreed to send war crimes investigators to Yemen, overcoming strong resistance from Saudi Arabia.

The Saudi-led coalition has been accused of air strikes in Yemen against areas controlled by the Huthis, including Saada.

The coalition accuses the Huthis of using civilians as human shields.

In June, more than 24 civilians were killed in an air strike on Saada's Mashnaq market, a centre for trafficking in qat, a leafy stimulant plant that is widely used in Yemen but illegal in Saudi Arabia.

Source: AFP