The United Nations has warned that Yemen could face the worst famine in a century if a Saudi Arabia-led coalition does not halt airstrikes, The Guardian reported. UN’s Humanitarian Coordinator for Yemen, Lise Grande, told the BBC that 12 to 13 million civilians could starve to death.

“I think many of us felt as we went into the 21st century that it was unthinkable that we could see a famine like we saw in Ethiopia, that we saw in Bengal, that we saw in parts of the Soviet Union – that was just unacceptable,” said Grande. “Many of us had the confidence that would never happen again and yet the reality is that in Yemen that is precisely what we are looking at.”

Grande said that Yemen could be in the grip of a famine in the next three months if the war went on. A civil war has engulfed the country after Iranian-backed Houthi rebels captured large areas, including the capital Sana’a. The Saudi-led coalition, backed by the United States, has been fighting the rebels since 2015.

“There’s no question we should be ashamed, and we should, every day that we wake up, renew our commitment to do everything possible to help the people that are suffering and end the conflict,” said Grande.

The UN also condemned an attack on passenger buses that killed at least 15 civilians and injured 20 others in Jabal Ras district on Saturday. “The UN agencies working in Yemen unequivocally condemn the attack on civilians and extend our deepest condolences to the families of the victims,” Grande said on Sunday. “Belligerents must do everything possible to protect civilians – not hurt, maim, injure or kill them.”

The UN has described Yemen as “the world’s worst humanitarian crisis”, with close to 75% of its population requiring some form of humanitarian assistance and protection.