US Gen David Petraeus has formally taken command of the 130,000-strong international force battling insurgents in Afghanistan.
The general, whose strategy in Iraq won praise and reduced violence, took over at a modest military ceremony in Kabul.
Hoping to repeat his Iraq success, the general insists Nato and the Afghan government must work hand-in-hand.
As an indication of his task, June was the deadliest month for foreign troops since 2001, with 102 killed.
Gen Petraeus has already warned that Taliban militants are confident and resilient, and he takes command at a time when the war is entering a difficult phase, the BBC’s Quentin Sommerville reports from Kabul.
The general arrived in Afghanistan on Friday night and spent Saturday meeting US, Afghan and other officials.