US President Barack Obama and Afghan President Hamid Karzai will discuss matters of war - including future US troop levels and Afghanistan's army - when they meet on Friday, but matters of peace may be the most delicate item on their long agenda.

After nearly 10 months in limbo, tentative reconciliation efforts involving Taliban insurgents, the Karzai government and other major Afghan factions have shown new signs of life, resurrecting tantalizing hopes for a negotiated end to decades of war.

Pakistan, which US and Afghan officials have long accused of backing the insurgents and meddling in Afghanistan, has recently signaled an apparent policy shift toward promoting its neighbor's stability as most US combat troops prepare to depart, top Pakistani and Afghan officials said.

In another potentially significant development, Taliban representatives met outside Paris last month with members of the Afghan High Peace Council - although not directly with members of the Karzai government, which they have long shunned.

US officials, speaking on condition of anonymity, said the developments are promising, but major challenges remain to opening negotiations, let alone reaching an agreement on the war-ravaged country's political future.

Hopes for Afghan peace talks have been raised before, only to be dashed. Last March, the Taliban suspended months of quiet discussions with Washington aimed at getting the insurgents and the Karzai government to the peace table.

Obama is expected to press the Afghan president to bless the formal opening of a Taliban political office in the Gulf state of Qatar as a way to jump-start inter-Afghan talks.

Karzai has been lukewarm to the idea, apparently fearing his government would be sidelined in any negotiations.