At least five medical workers were killed and 10 others wounded when an explosive projectile slammed into a Doctors Without Borders/Médecins Sans Frontières (MSF)-affiliated medical facility in the Shiara Hospital in Razeh district on Sunday. The attack on the hospital, which led to the destruction of multiple buildings within the MSF-linked center, came amid an ongoing surge of fighting in Yemen’s northern province of Saada. As of Monday afternoon, rescuers continued to work through the rubble, where more medical staff and patients are believed to be trapped.

MSF officials remained uncertain whether the explosion was caused by an airstrike or by a missile fired from ground forces. The identity of the attackers also remains contested, with reports from the Houthi-controlled SABA news agency asserting that the attack was launched by the Saudi coalition forces and US media reports maintaining that the origins of the strike are still not known.

All of the opposing military forces and militias in the area were repeatedly warned about the location of the MSF hospital, which had been operating at the same location for years, according to MSF operations chief Raquel Ayora.

“All warring parties, including the Saudi-led coalition (SLC), are regularly informed of the GPS coordinates of the medical sites where MSF works and we are in constant dialogue with them to ensure that they understand the severity of the humanitarian consequences of the conflict and the need to respect the provision of medical services,” Ayora said.

“There is no way that anyone with the capacity to carry out an airstrike or launch a rocket would not have known,” Ayora said.

An MSF statement described the attack as the third “severe” strike to be suffered by MSF’s network in Yemen, with both previous attacks being launched by the Saudi-led coalition. On October 27, Saudi strikes completely destroyed MSF’s Hospital Haydan, and another round of Saudi coalition attacks struck an MSF medical center in the city of Taiz on December 3.

While its precise origins remain unconfirmed, there is every reason to assume that the attack was carried out as a deliberate act of terror against the medical charity and the civilian population of Yemen, more than likely by Saudi forces and their Gulf state allies.

Even in the unlikely event that non-Saudi forces were immediately behind Sunday’s attack, ultimate responsibility for the deaths of at least five medical workers, and the destruction of yet another medical facility in a country where the vast majority lack access to medical care, lies squarely with Washington and Riyadh.

The Saudi-led war itself has been made possible only through the close support and collaboration of US forces, which have coordinated the war from the beginning from a joint US-Saudi military cell in Riyadh. US military personnel have provided intelligence and target lists to the Saudi war coalition, and have flown thousands of mid-air refueling missions, enabling Saudi jets to remain airborne for multiple bombing runs.

The weapons used by the Saudi and Gulf militaries against countless civilian targets across Yemen have been overwhelmingly supplied by US companies, including a $1.3 billion arms package authorized by the Obama administration in November. Armed to the teeth with US-made weaponry and guided by the US military’s target spotters and logistics specialists, the Saudi coalition has struck literally dozens of other hospitals in Yemen in the course of the war, along with wedding parties, residential areas, and a center that provides assistance to the blind.

The conditions which gave rise to the latest hospital bombing, along with the dozens of other such attacks that have occurred during the 10-month-old war, are ultimately the outcome of the US-backed Saudi war, and, more broadly, the efforts of the US and its Saudi allies to maintain their dominance over the entire region through ever growing doses of military violence.

Over the past decade and a half, in the name of fighting the Islamic militia Al Qaeda in the Arabian Peninsula, US forces have carried out years of covert and drone warfare throughout Yemen. The rapid successes achieved by the Houthi insurgency against former president Ali Abdullah Saleh Saleh’s successor, Abd Rabbuh Mansur Hadi, were enabled by the widespread hatred toward the US-backed government produced by its collaboration with the secret US war and the endless series of assassinations and kidnapping raids carried out by US forces.

Saudi forces have used illegal cluster munitions against civilian areas on multiple occasions, as documented in separate reports by the United Nations and Human Rights Watch. Last Wednesday, one day after Saudi forces destroyed the blind persons’ medical center, the Saudi coalition deployed cluster bombs against residential neighborhoods in the Yemeni capital of Sanaa.

“The coalition’s repeated use of cluster bombs in the middle of a crowded city suggests an intent to harm civilians,” Human Rights Watch weapons chief Stephen Goose said. “The coalition seems less concerned than ever about sparing civilians from war’s horrors,” he added.

The weapons used were likely provided to the Saudis by the US, Goose said. The US government knew that the Saudi coalition was deploying the illegal weapons, an unnamed US official confirmed in statements cited by US News and World Report in August.

Nearly 3,000 civilians have been killed overall in fighting since the beginning of the Saudi-led war on March 30, according to the UN. Over 21 million Yemenis, or more than 80 percent of the population, now require some form of humanitarian aid.