"We now have a plan in place, a campaign plan, endorsed in Chicago by NATO, that has strong international support," Panetta, who recently returned from Afghanistan, said while speaking at the National Press Club in Washington.
"We've reversed a five-year trend of growing violence. The Taliban to this day [have] not been able over this last year to regain any of the territory they lost."
Panetta said Afghan security forces, trained by coalition forces, are on track to take the lead in securing their entire country next year as the coalition forces continue to transition both governance and security to the Afghans. U.S. and NATO forces are scheduled to end all their combat operations by the end of 2014.
Panetta said 75 percent of the Afghan population has now been transitioned to Afghan security and control, and that figure will reach 100 percent next year.
"But we've also made clear that our commitment to Afghanistan, as we draw down by the end of 2014, our commitment will continue," Panetta said. "We are transitioning; we are not leaving. We will maintain an enduring presence aimed at supporting Afghan forces and ensuring the mission that we were embarked on in Afghanistan, the mission that al-Qaida never again regains Afghanistan as a safe haven from which to attack the United States or our allies."
He said during his latest trip to Afghanistan, he met with all military commanders and all of them "believe that we have fundamentally turned the tide in that effort, after years in which we lacked the right strategy and the necessary resources to try to achieve the mission we are embarked on."
Panetta said after 10 years of continuous warfare, the United States is truly at a critical point as large-scale conflicts in Iraq and Afghanistan wind down.
"An era of blank-check defense spending is over, and forces will be reduced. And all of this occurs as the United States faces an array of asymmetric threats in the world," he warned, adding threats to U.S. security and its global interests are not receding.
"This means that the military services must remain vigilant, they must remain strong, they must remain prepared to operate in a way that differs significantly from the past."