The bombardment on the Mdecins Sans Frontires (MSF) hospital on Saturday morning went on for more than half an hour despite the charity raising the alarm with American officials.
The medical aid organization said at least 12 of its staff and seven patients were killed while some 37 people were seriously injured, 19 of them MSF staff.
The UN human rights chief said on Saturday the deadly airstrike constitutes a grave violation of international law and "may amount to a war crime."
Obama on Saturday offered his "deepest condolences" over the deadly airstrike and promised a thorough investigation into 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," Obama said in a statement.
"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," he added.
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Injured Mdecins Sans Frontires staff are seen after an airstrike struck their hospital in Kunduz. (AP photo)[/caption]UN High Commissioner Zeid Ra'ad al-Hussein said earlier in the day that the attack on the medical center was "utterly tragic, inexcusable, and possibly even criminal."
"This deeply shocking event should be promptly, thoroughly and independently investigated and the results should be made public," Zeid said in a statement.
"The seriousness of the incident is underlined by the fact that, if established as deliberate in a court of law, an airstrike on a hospital may amount to a war crime," the UN human rights chief stated.
By Press TV
