Walid al-Ibbi, 35, a barber from Saada city in northwest Yemen, is one of only four members of his family left alive. A few days ago, he sat with me in a garden in Sanaa, the capital, sharing pictures of his late wife and daughters. Over and over he repeated the words, “I can’t believe I’ve lost my family.” He struggled to hold back tears as he read out the names of all 27 of his family members — including 14 children — who were killed when airstrikes by the Saudi Arabia-led coalition hit his father’s house on May 5.

Ibbi is now shuttling between two hospitals in Sanaa, where his father and brother, who survived but were both wounded, are receiving treatment.

His brother has a metal fragment lodged in his forehead against his optical nerve. Doctors say that he may go blind when they remove it. Ibbi, the only family member who survived unwounded, worked with his brothers in two barbershops that the family owned in the city. None of them had any obvious links to the Houthis, the target of the coalition’s aerial bombardment of Yemen. “I don’t know anyone here in the capital,” Ibbi told me. He was in traditional Saada dress and looked out of place on the streets of Sanaa where we met up with him. “I feel very uncomfortable and alone. I just want to go home, but I have nothing to go back to.”

On March 26, a 10-member coalition made up of Sunni states led by Saudi Arabia launched airstrikes on the Houthis, an Iranian-supported militia movement that has taken control of large swaths of Yemen, including the capital, since September 2014. In January, they surrounded the presidential palace, forcing President Abed Rabbo Mansour Hadi and his cabinet to resign. Hadi retreated to Aden, in the south, which had been his base, but left after the Houthis extended their military campaign there. In April, Hadi reassembled his government in Saudi Arabia. He endorsed the coalition’s airstrikes and called for it to send ground forces into Yemen.

It’s possible that the Ibbi family had connections to the Houthis they didn’t wish to reveal to us. Even if that is the case, though, it is hard to see how an attack that killed so many civilians — mainly women and children — can be justified under the laws of war, which require that any harm to civilians must be proportionate to the anticipated military gain. On a visit to the Houthi stronghold of Saada city during a five-day ceasefire in the middle of May, I heard of at least four other families whose homes the coalition had struck, each time killing children and women and leaving few survivors. Saada city, a historic mud brick agricultural town in northern Yemen, is normally home to about 50,000 people. It has experienced the full force of the coalition’s bombing campaign, with Saudi forces dropping bombs on a massive scale.

My colleague and I found Saada city littered with craters, debris, and destroyed buildings. It appeared that the coalition is able to hit targets it identifies because government buildings, such as ministry offices, the governor’s home, and the courthouse, had all been damaged. Some — particularly those containing security installations — may have been legitimate military targets. Yet it is difficult to see what military objective might have motivated strikes on the post office and the center for combatting illiteracy, both of which were destroyed.

The fact the coalition seems capable of targeting government buildings with some precision makes it hard to explain why family homes have also been hit, defying restrictions on doing harm to civilians under the laws of war. We also saw the ruins of Saada city’s four main markets, which have all been damaged by the coalition air campaign. Airstrikes have also taken out the community’s main electricity and water supply installations and some food warehouses.

In Saada city we met a group of a dozen men from the “human rights implementation office” of Ansar Allah, the Houthis’ political and military organization. As far as we could see, they had been put in charge of managing day-to-day affairs in the city while the highest Houthi officials moved elsewhere to escape the coalition’s heavy bombardment.

One night the men treated us to dinner. We sat on the floor in a room that hadn’t been cleaned for some time, and all of our hosts were wearing clothes covered in stains — things that would have been socially unacceptable in peacetime. They each went to the bathroom before the meal to rinse their faces and run water through their hair; they told us how lucky they were to still have a bit of running water and a cube of soap. One of them, Fahmi, apologized, saying he had tried hard but unsuccessfully to find chicken and rice. Instead, the dinner consisted of olives, two cans of cheese, canned tuna, and canned sweet cream. “We would normally offer you a better meal but all our wives have left, so we have to fend for ourselves and there is less and less we can find here,” he explained.

If these men have to resort to the depleting stores of canned food to survive, one can only imagine how bad things are for the ordinary families who have stayed in Saada, unable to leave when Saudi Arabia declared the city a military target. Such a strategy violates the laws of war, which prohibit attacks that treat distinct military objects in an area containing a similar concentration of civilians or civilian objects as a single military objective.

We asked the men about conditions in Saada’s border regions with Saudia Arabia, where neither the coalition nor Houthi forces have respected the recent ceasefire. (Reliable news from these areas is hard to come by, given that the bombings have also crippled the phone networks.) We managed to interview one man from Baqim, a town 10 kilometers from the Saudi border, who told us that on April 29, four of his acquaintances were wounded when they picked up a metal canister with a red ribbon hanging from it they had found lying on the ground. It was an unexploded cluster munition, and detonated when they picked it up.

Throughout Saada city, we found various types of ordnance. Some of the unexploded munitions we found, like BLU-108 canisters that resemble tin biscuit containers, were small enough to attract children as playthings, strewn among the rubble. Others — including dumb bombs as big as people, too heavy to be readily moved — lay among the ruins of near-demolished offices. It’s unclear when Yemen will once again have a government in place that can clear these dangerous objects from the affected areas, let alone begin rebuilding the civilian infrastructure that has been destroyed. Yemen was already mired in economic and humanitarian crisis before the war began, and now over half a million people have had to flee their homes, adding to the thousands already internally displaced. The challenges to the country’s recovery are immense.

My colleague and I left Yemen a few days ago, taking a 20-hour voyage to Djibouti with 405 Yemenis on a boat equipped for transporting cattle.

As the hours passed, we heard families asking each other where they would go next, what awaited them, and when they would be able to return.

As I listened, I asked myself what will be left of Yemen if and when they do return. Based on what I saw in Saada, the coalition airstrikes are affecting and killing civilians in ways that are hard to justify, even accepting the harsh reality of conflict. The coalition, and countries providing it military support, have strict obligations not only not to deliberately target civilians — a war crime — but also not to carry out indiscriminate or disproportionate attacks that lead to civilian deaths and harm.

For the future of Yemen’s civilians, the coalition needs to commit to respecting these fundamentals of international humanitarian law. It’s too late for most of Walid al-Ibbi’s family. But for the many Yemenis who are displaced within the country and those who have fled to neighboring countries, the coalition must ensure they have something to return to when the fighting ends.

Note: This article originally incorrectly dated the airstrike on Abdullah al-Ibbi’s house as taking place on May 6, 2015. The attack took place on May 5, 2015. The date has been subsequently corrected in the version of this article posted on the HRW website.