Two children were killed and eight wounded in an airstrike on the northern Yemeni Houthi stronghold of Saada, a UN agency said on Wednesday.

A Saudi-led military coalition allied with Yemen's government is the only party known to conduct air raids over areas controlled by Yemen's Houthis.

The United Nations Children's Fund tweeted that two children died and eight were wounded in an air raid on Saada governorate on Tuesday.

"For how long must #ChildrenUnderAttack in Yemen continue to be killed when it can be avoided?" UNICEF asked.

The coalition, which has fought the Houthis since 2015, was last year blacklisted by the UN for the killing and maiming of children.

More than 10,000 people have been killed and tens of thousands wounded in Yemen's three-year-old war, which is seen as both a civil conflict and a proxy war between regional titans Saudi Arabia and Iran.

The war has triggered what the UN calls the world's largest humanitarian disaster, with 8.4 million people now facing imminent famine. Yemen is also battling cholera and diphtheria outbreaks.

-Agencies