US President Barack Obama on Saturday offered his "deepest condolences" over a suspected US airstrike on a hospital in the Afghan city of Kunduz that killed 19 people, and promised a thorough probe of the incident.
"On behalf of the American people, I extend my deepest condolences to the medical professionals and other civilians killed and injured in the tragic incident at a Doctors Without Borders hospital in Kunduz," he said in a statement released by the White House.
"The Department of Defense has launched a full investigation, and we will await the results of that inquiry before making a definitive judgment as to the circumstances of this tragedy," Obama said.
The attack early on Saturday left the building engulfed in flames, and dozens more people seriously wounded, with photos posted by Medecins Sans Frontieres (Doctors Without Borders) showing their staff shocked and dazed.
MSF said the aerial raid hit the main hospital building housing the intensive care unit and emergency rooms, while the surrounding buildings were left untouched.
"I have asked the Department of Defence to keep me apprised of the investigation and expect a full accounting of the facts and circumstances," Mr Obama said.
"Michelle and I offer our thoughts and prayers to all of the civilians affected by this incident, their families, and loved ones."
He added: "We will continue to work closely with President (Ashraf) Ghani, the Afghan government, and our international partners to support the Afghan National Defense and Security forces as they work to secure their country."
UN Human Rights chief Zeid Ra'ad Al Hussein led a chorus of condemnation, without saying who carried out the strike, noting that an assault on a hospital could amount to a war crime. "This event is utterly tragic, inexcusable, and possibly even criminal," he said.
UN Secretary-General Ban Ki-moon called for a thorough and impartial investigation "in order to ensure accountability."
The medical charity said its staff phoned military officials at NATO in Kabul and Washington during the morning attack, but bombs continued to rain down for nearly an hour.
"All indications currently point to the bombing being carried out by international Coalition forces," MSF said, demanding "a full and transparent account".