War-torn Yemen is on the brink of famine, with millions of women and children most at risk of starvation as fighting around major ports stalls imports of food and other humanitarian aid, according to the United Nations.
Some 13 million people in the impoverished Arab state, half the population, are hungry, while 6 million face starvation and urgently need food aid, the World Food Programme said.
Warplanes from a Saudi-led coalition earlier this week hit the port of Hodeida, controlled by Iranian-allied Houthi forces, which has become the main access point for aid to the north.
The war has killed more than 4,300 people, many of them civilians, and spread disease and hunger throughout Yemen.
The lack of basic foodstuffs, shortage of clean water, and diminished fuel supply have created "the dawn of a perfect storm for the most vulnerable Yemeni people", according to WFP Executive Director Ertharin Cousin.
The warning signs of looming famine "are in fact developing in front of our eyes," Cousin said in a statement on Wednesday.
"The damage to Yemen's next generation may become irreversible if we don't reach children quickly with the right food at the right time. We must act now before it is too late."
More than 1.2 million children in Yemen are suffering from malnutrition and more than half a million children are severely malnourished, according to the WFP.
The 1.3 million internally displaced people have been hit hardest by the lack of food, with many families surviving on bread, rice and tea, the U.N. body said.
The WFP has supplied 3.5 million people with food since the conflict erupted, but said damage to road networks had made it difficult to reach the hardest-hit areas.
Yemen previously imported the majority of its fuel and 90 percent of the food needed for its population of 26 million, most of it by sea, but the Saudi alliance has imposed a blockade on imports in a bid to cut off arms supplies to rebel forces.
United Nations aid chief Stephen O'Brien said earlier this week that the bombing of Hodeida was a violation of international humanitarian law and that the damage to the port would make it harder to get aid to those in need.
The United Nations has raised the humanitarian crisis in Yemen to its highest category, placing it alongside emergencies in South Sudan, Syria and Iraq. It has said more than 21 million people in Yemen need help, some 80 percent of the population.