Gen. David Petraeus formally assumed command of NATO's International Security Assistance Force during a ceremony Sunday at the command's headquarters in Kabul.
In a speech Saturday, Petraeus called for unity on all fronts of the war in Afghanistan.
"I'm reminded we must achieve unity of effort and common purpose,"Petraeus told a crowd of about 1,700 at the U.S. Embassy in Kabul. "Civilian and military, Afghan and international. We are part of one team with one mission." Petraeus was tapped by President Barack Obama as the new top U.S. military commander in Afghanistan to replace Gen. Stanley McChrystal.
McChrystal was relieved of his duties after the general and his staff were quoted in a Rolling Stone magazine article criticizing and mocking key administration officials.
The Senate unanimously confirmed Petraeus for the new position in late June. He arrived in Afghanistan on Friday.
Petraeus has said he supports Obama's plan to begin withdrawing U.S. troops from Afghanistan in July 2011 - but insists it ought to be based on "conditions on the ground.