KABUL—The top commander of U.S. troops in Afghanistan said Wednesday that the American service members most closely associated with the deadly bombing of a Doctors Without Borders hospital in Afghanistan have been suspended from duty.

On Oct. 3, a U.S. gunship repeatedly bombed a compound run by the humanitarian organization Doctors Without Borders, or Médecins Sans Frontières, in the northern city of Kunduz. At least 30 people died in the attack, which the group has said may constitute a war crime.

Presenting the findings of a U.S. military investigation into the incident, U.S. Army Gen. John Campbell, who commands U.S. and allied troops in Afghanistan, said some of the Americans involved didn’t follow the rules of engagement. He said some of them have been suspended from their duties pending a disciplinary review.

During a press briefing on Wednesday, Gen. Campbell said the probe found “the personnel who requested the strike and those who executed it from the air did not undertake the appropriate measures to verify that the facility was a legitimate military target.”

Gen. Campbell didn’t take questions. His spokesman declined to say how many U.S. military service members had been suspended because of the incident.