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.