In the phone call, Obama "extended his condolences to the people of Afghanistan, and made clear his administration`s commitment to establish the facts as quickly as possible and to hold fully accountable anyone responsible," the White House said.
Obama had earlier issued a statement saying that "this incident is tragic and shocking, and does not represent the exceptional character of our military."
The shooting spree erupted early Sunday when a US soldier walked out of his base in southern Kandahar province and opened fire on men, women and children in a rampage that has raised new questions about the long-term viability of the US mission.
US Defense Secretary Leon Panetta assured Karzai in a phone call Sunday that a "full investigation" was under way.
The shooting comes as Washington`s relations with its Afghan partners have plunged to an all-time low -- a Koran burning incident last month sparked days of deadly riots -- putting immense strains on a military mission that is now over a decade old and only getting messier with time.
It also seems certain to complicate Washington`s efforts to negotiate a long-term strategic partnership with Kabul that would set the basis for a continuing security relationship. (*)
Editor: Kunto Wibisono
Copyright © ANTARA 2012
