President Obama apologized to the humanitarian group Doctors Without Borders after a US airstrike on its hospital in Afghanistan killed at least 22 doctors, medical workers, and patients. The president called it “a mistake.” Doctors Without Borders released cell phone video of the damage to its hospital. The group is demanding an independent investigation into what it considers a war crime. Its leaders said they alerted US military officials that the hospital was under attack, but the bombing continued for at least a half-hour. Deliberately targeting a medical facility is a violation of international law.