"For more than a year, General Allen has served with distinction as the Commander of US Forces and NATO International Security Assistances Forces in Afghanistan, seeing us through a critical period in our military efforts and in Afghanistan's transition," Obama said.
Pakistan Army chief Gen Ashfaq Parvez Kayani on Thursday called for transparent ties with US based on mutual trust as he met American commander in Afghanistan, days after the two sides struck a deal ending a seven-month blockade of NATO supply routes.
Two top United States officials have called off visits to Islamabad without assigning any reasons, reflecting the current tensions between the two countries as they struggle to reset their troubled ties a year after the killing of Al Qaeda's Osama bin Laden.
A top American commander based in Afghanistan has submitted plans to the Pentagon that would keep 6,000 to 20,000 US troops in the war-torn country after 2014.
The United States may keep a combat force of around 10,000 in Afghanistan, including a small counter-terrorism force after 2014 as a contingency against re-emergence of the Al Qaeda.
Central Intelligence Agency Director Leon Panetta will move to Pentagon to become new US Defence Secretary to replace Robert Gates while his top military commander in Afghanistan Gen David Petraeus is to takeover as the new CIA Director.
United States President Barack Obama has chosen retired Marine Corps General John Allen, who earlier served as the commander of the US and North Atlantic Treaty Organisation forces in Afghanistan, to head the America-led global coalition against the dreaded terror group Islamic State, earlier know as ISIS (Islamic State of Iraq and Syria).
Bruce Riedel, a former CIA analyst who was one of the key architects of US President Barack Obama's Af-Pak policy during his first term, has called for an offensive strategy against terrorist networks and this includes hitting out at terrorist groups inside Pakistan.