"This fight will go until a political settlement," Army Gen. Scott Miller, the commander of U.S. Forces-Afghanistan and the Resolute Support mission there, told CNN when asked whether the Afghan campaign against the Taliban had reached a stalemate.

"These are two sides that are fighting against one another, and neither one of them will achieve a military victory at this stage."

In the same interview, U.S. ambassador to Afghanistan John Bass concurred with Miller's assessment, cautioning that U.S. and Afghan officials will face a complicated diplomatic situation given the Talian's aggressive rejection of the current administration in Kabul.

"We have an opportunity today that we didn't have six or 12 months ago to see if it's truly possible to achieve that political settlement," Bass told CNN.