A hospital associated with Doctors Without Borders. A school. A potato chip factory. Under international law, those facilities in Yemen are not legitimate military targets. Yet all were bombed in recent days by warplanes belonging to a coalition led by Saudi Arabia, killing more than 40 civilians.

The United States is complicit in this carnage. It has enabled the coalition in many ways, including selling arms to the Saudis to mollify them after the nuclear deal with Iran. Congress should put the arms sales on hold and President Obama should quietly inform Riyadh that the United States will withdraw crucial assistance if the Saudis do not stop targeting civilians and agree to negotiate peace.

The airstrikes are further evidence that the Saudis have escalated their bombing campaign against Houthi militias, which control the capital, Sana, since peace talks were suspended on Aug. 6, ending a cease-fire that was declared more than four months ago. They also suggest one of two unpleasant possibilities. One is that the Saudis and their coalition of mostly Sunni Arab partners have yet to learn how to identify permissible military targets. The other is that they simply do not care about killing innocent civilians. The bombing of the hospital, which alone killed 15 people, was the fourth attack on a facility supported by Doctors Without Borders in the past year even though all parties to the conflict were told exactly where the hospitals were located.

In all, the war has killed more than 6,500 people, displaced more than 2.5 million others and pushed one of the world’s poorest countries from deprivation to devastation. A recent United Nations report blamed the coalition for 60 percent of the deaths and injuries to children last year. Human rights groups and the United Nations have suggested that war crimes may have been committed.