Afghan President Hamid Karzai's contention that the United States was colluding with the Taliban is "categorically false," the commander for the NATO-led forces in the country said Monday.

"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 Marine Gen. Joseph Dunford, the commander of the International Security Assistance Force.