Exclusive - Shift by hard-line Taliban factions may have sealed prisoner exchange

U.S. President Barack Obama watches as Jami Bergdahl (L) and Bob Bergdahl (C) talk about the release of their son, prisoner of war U.S. Army Sergeant Bowe Bergdahl, during a statement in the Rose Garden at the White House in Washington May 31, 2014. REUTERS/Jonathan Ernst

WASHINGTON (Reuters) - The breakthrough leading to Saturday's surprise exchange of a U.S. prisoner of war for five Guantanamo detainees suddenly became possible after harder-line factions of the Afghan Taliban apparently shifted course and agreed to back it, according to U.S. officials.

The United States had tried diplomacy since late 2010 to free Army Sergeant Bowe Bergdahl, held captive in Afghanistan for nearly five years. But the efforts came to little until now.