An unconfirmed but large number of civilians, including children, were killed in air strikes in northern Yemen on Thursday, the United Nations said.
Field reports indicate that as many as nine children were killed and seven children and two women were injured, humanitarian coordination agency UNOCHA said in a statement on Friday about strikes that hit al-Jawf governorate.
This is the fourth such attack since June causing multiple civilian casualties.
The UN's Yemen envoy called for a transparent investigation into the incident.
The health ministry for Houthi-held parts of Yemen said 9 children had died and 12 children and women had been injured in a number of strikes by aircraft of the Saudi-led coalition.
Medical and civilian sources told Reuters a number of civilians had been killed by strikes in Jawf and transferred to hospitals.
The coalition, which is fighting the Iranian-aligned Houthi movement, said on Thursday it shot down an explosive-laden drone heading towards Saudi Arabia.
Cross-border attacks by Houthi forces have escalated since late May when a truce prompted by the coronavirus pandemic expired. In late June, missiles reached the Saudi capital Riyadh. The coalition has retaliated with air strikes.
"I remind all actors that they have obligations under international law to protect civilians and civilian objects. We continue to work with the parties to reach an agreement on a nationwide ceasefire," envoy Martin Griffiths said.
"Yemenis deserve better than a life of perpetual war."
The coalition, which receives weapons and intelligence from Western allies including the United States and Britain, was last month removed from a UN blacklist several years after it was first accused of killing and injuring children in Yemen.
The conflict has killed more than 100,000 people since the alliance intervened in Yemen in March 2015 shortly after the Houthis ousted the Saudi-backed government from power in Sanaa.
The conflict is largely seen regionally as a proxy war between Saudi and Iran. The Houthis say they are fighting a corrupt system.