Petraeus hands over Afghan command

Petraeus oversaw a surge of 30,000 extra US forces which helped stop the momentum of a growing insurgency,especially in the Taliban heartland in the south.

However,despite gains,the Taliban is still far from quelled.

We should be clear-eyed about the challenges that lie ahead, Petraeus said at a ceremony to mark the change of command of the NATO-led International Security Assistance Force ISAF to US Marine Corps General John Allen.

Underlining those challenges,ISAF said Monday three of its troops had been killed by a bomb in Afghanistans east. Eleven Afghan police were also killed on Monday,seven of them in an attack by Taliban on a police checkpoint in the city of Lashkar Gah.