(CNN) -- The NATO-led International Security Assistance Force has taken exception to Afghan President Hamid Karzai's comments that that the Taliban was colluding with the United States. "We have fought too hard over the past 12 years. We have shed too much blood over the past 12 years. We have done too much to help the Afghan Security Forces grow over the last 12 years to ever think that violence or instability would be to our advantage," said ISAF commander General Joseph Dunford.