“We are trapped in hell!” Those are the words of a Yemeni friend this week in the midst of the Saudi aerial bombardment of Sanaa. The war is escalating with Houthi missile attacks and the tightening of the blockade. How long will the international community — especially America and the United Kingdom — let the world’s worst humanitarian crisis continue when they have the power to end it?

Yemen is the worst humanitarian catastrophe in the world. Thirty months of war by the richest Arabs against the poorest Arabs has led to mass malnutrition, famine and disease. Cholera is rampant. A generation of Yemeni children will be malformed. The BBC has documented the tragedy in a series of devastating reports. The United Nations says 7 million people are on the brink of starvation.

The Saudi-led coalition has tightened the blockade of rebel-held northern Yemen since the rebels fired a ballistic missile at King Khaled International Airport outside of Riyadh on Nov. 4. The Saudis claim it was intercepted by a Patriot missile. Observers reported considerable debris around the airport. Saudi Arabia called the attack an act of war committed by Iran, which allegedly supplied the missile to the Houthi rebels.

Yemen has had an indigenous missile force for decades. Former North Yemeni President Ali Abdullah Saleh bought Scud missiles from North Korea in the 1980s, while the South Yemen communist government got them from Russia. Both sides used them extensively in the 1994 civil war, so there is a trained Yemeni military missile capability. The Royal Saudi Air Force and UAE air campaign failed to address the missile problem despite extravagant claims to the contrary at the start of Operation Decisive Storm in 2016.