Medical aid group Medecins Sans Frontieres (MSF) — also known as Doctors Without Borders — has announced it will withdraw from northern Yemen, in the wake of an airstrike by the Saudi coalition that struck one of its hospitals on Monday, killing 19 and wounding 24.

The New York Times notes this was the fourth facility supported by MSF to be hit by Saudi-led coalition airstrikes over the past 17 months. The Saudis and their allies have been running an air campaign against the Iran-backed Houthi insurgents who overthrow Yemen’s internationally-recognized government in 2015.

MSF said that airstrikes continue endangering its facilities despite the fact it has “systematically shared the GPS coordinates of hospitals in which the organization works with the parties involved in the conflict.”

The group announced in a statement:

MSF is withdrawing its staff members from Haydan, Razeh, Al Gamouri and Yasnim hospitals in Saada governorate and Abs and Al Gamouri hospitals in Hajjah governorate. The airstrike on Abs Hospital was the fourth and the deadliest attack on an MSF-supported medical facility during this war, while there have been numerous attacks on other health facilities all over Yemen.

MSF said it has met with high-ranking officials of the Saudi-led coalition in Riyadh on two occasions, “to ensure that humanitarian and medical assistance can reach Yeminis, as well as to seek assurances that attacks on hospitals would end,” but in the wake of the Abs Hospital bombing, it considers reassurances from the coalition “unreliable.”

The group also complained that Saudi coalition investigations into previous bombing incidents have not been shared with them, further shaking their confidence in the coalition’s ability to guarantee the safety of Doctors Without Borders personnel.

“This latest incident shows that the current rules of engagement, military protocols and procedures are inadequate in avoiding attacks on hospitals and need revision and changes. MSF asks the Saudi-led coalition and the governments supporting the coalition, particularly the U.S., U.K. and France, to ensure an immediate application of measures to substantially increase the protection of civilians,” said MSF general director Joan Tubau.

MSF said it “deeply regrets the consequences of this evacuation” and “hopes the security situation will improve so that the population will have some respite, and MSF teams will be able to return to providing much-needed medical care.”

The group further regrets “the collective failure to protect Yemeni civilians from military action and to provide an adequate humanitarian response,” including the Houthis and their allies in its criticism.

“Saudi officials have accused the Houthi militias, who control Sana, the capital, and northern Yemen, of using hospitals, schools and other civilian facilities to hide their military forces. Doctors Without Borders has denied that was the case in any of its bombed health facilities,” the New York Times reports.

The Belfast Telegraph observes that it has been a rough year for MSF around the world, with at least 100 staff members, patients, and caretakers killed, and another 130 wounded, in “aerial bombing and shelling attacks on more than 80 MSF-supported and run health structures in 2015 and early 2016.”

At the UK GuardianTrevor Timm accuses the United States of being an accessory to war crimes by supporting the “appalling” Saudi war in Yemen, a “campaign of indiscriminate killing” that has been in progress for the past year and a half:

This US-backed war is not just a case of the Obama administration sitting idly by while its close ally goes on a destructive spree of historic proportions. The government is actively selling the Saudis billions of dollars of weaponry. They’re re-supplying planes engaged in the bombing runs and providing “intelligence” for the targets that Saudi Arabia is hitting.

Put simply, the US is quite literally funding a humanitarian catastrophe that, by some measures, is larger than the crisis in Syria. As the New York Times editorial board wrote this week: “Experts say the coalition would be grounded if Washington withheld its support.” Yet all we’ve heard is crickets.

Timm faults both the Clinton and Trump campaigns for failing to address the situation in Yemen, and criticizes a mainstream media blackout interrupted only by Sen. Chris Murphy (D-CT) complaining to Jake Tapper of CNN on Wednesday that Congress isn’t debating the “unauthorized” war in Yemen.

“If you talk to Yemenis, they will tell you that inside Yemen this is not perceived to be a Saudi bombing campaign, this is a US bombing campaign. What’s happening is we are helping to radicalize the the Yemeni population against the United States,” Murphy said.