Afghan President Hamid Karzai has suspended security talks with the U.S. in protest following a Taliban group's announcement it would hold its own talks with Washington.
Hours after the Taliban announcement, the group claimed responsibility for an attack in Afghanistan that killed four U.S. troops.
Taliban spokesman Zabiullah Mujahid said today that the militants fired two rockets into the Bagram Air Base late on Tuesday.
American officials confirmed the base had come under attack by indirect fire - likely a mortar or rocket - and that four U.S. troops were killed.
The attack underscores the challenges ahead after the Taliban and the U.S. announced they would hold talks in Qatar to try and negotiate a solution to the violence. President Barack Obama has cautioned this would be neither quick nor easy.