WASHINGTON — It was a frenetic Monday afternoon at Abs Hospital in northern Yemen, with doctors and nurses busily shuttling among the patients and a maternity ward filled with 25 women expecting to give birth.

The bomb from the Saudi jet dropped into the middle of the hospital compound, a facility run by Doctors Without Borders, landing between the emergency room and a triage area for new patients. Nineteen people were killed, dozens were injured, and a humanitarian group that for decades has braved war zones across the globe decided it had had enough.

Doctors Without Borders announced in the days after the Aug. 15 strike that it was pulling out of six medical facilities in northern Yemen, the latest turn in a war that has further devastated one of the Arab world’s poorest countries and has bogged down a Saudi military ill-prepared for the conflict.

For the Obama administration, it was another public reminder of the spiraling violence of a war in which it has played a direct role. American officials have publicly condemned the hospital bombing — and the bombing of a school two days earlier — but the Pentagon has given steady support to the coalition led by Saudi Arabia, with targeting intelligence and fuel for the Saudi planes involved in the air campaign.