"We are the owners of this soil, Americans aren't," Karzai said in a speech to young Afghan military officers in Kabul.
"Fortunately they are leaving soon," he added, referring to the foreign deployment against al-Qaeda and Taliban forces that started soon after the September 11 attacks of 2001.
The Afghan president was addressing hundreds of Afghan military officials and officers in an event held under tight security in a newly constructed military academy.
"To defend our soil, we don't need foreign troops," Karzai insisted to a round of applause from the audience. "My soil will be defended by these young officers."
Ties between Karzai and Washington have soured during the more than decade-long military campaign, with Afghanistan angered by civilian casualties in the war and the United States complaining of widespread corruption under Karzai's rule.
The NATO-led forces, numbering around 90,000, have started pulling out of Afghanistan and are due to end combat operations there by the end of 2014.
US President Barack Obama in his State of the Union speech last week said that tens of thousands of American troops had already come home, with more to follow soon, and that "by the end of next year, our war in Afghanistan will be over."
He said the United States will have met its objective "of defeating the core of al-Qaeda" and that "today, the organization that attacked us on 9/11 is a shadow of its former self."
Beyond 2014, "the nature of our commitment will change," he said, pointing to ongoing talks with Kabul on training and equipping Afghan forces so they can hunt al-Qaeda remnants and to ensure "that the country does not again slip into chaos."