At a rally in Kabul, he was asked how long Afghanistan would host foreign troops -- some 17,000 under U.S. military command, plus another 8,000 in the NATO-led international stabilization force.
He said that "[Foreign troops] are here temporarily. Even now, we have only managed to keep them here with thousands of pleadings and lamentations. We show our gratitude to them daily. They will go when we have a powerful army."
Karzai's statement comes amid heightened concern about security in the run-up to the 9 October election.
The threat posed by remnants of the Taliban regime and by allied Islamic militants was vividly demonstrated on 16 September when Karzai survived an assassination attempt in the town of Gardez.
A day later, the U.S. ambassador to Afghanistan, Zalmay Khalilzad, warned of an increase in violence by militants who want to disrupt the poll.
Today, it was the turn of Interior Minister Ali Ahmad Jalali.
He said his ministry had received information that Taliban militiamen and Al-Qaeda-led insurgents are preparing for attacks and had established bases along the porous Afghan-Pakistani border.
The assassination attempt also sparked renewed pleas from the UN Security Council for more troops, equipment, and funds for the NATO-led troops. The 15-member Security Council made the request as it unanimously agreed to renew the mandate of the International Security Assistance Force for another year, until October 2005.
More than 1,000 people have already died in militant-related violence across Afghanistan in the past year, including 12 election workers in the period from May to August alone.
Questions have also been raised over holding an election in a country in which various armed factions still wield considerable influence.
Clashes broke out in the western city of Herat last week when Karzai effectively dismissed powerful local commander Ismail Khan from his position as governor.
"Ismail Khan has been promoted to be a minister here because of his services and I'd like him, if I'm elected again by the Afghan people, I'd like him to be part of my cabinet in the future as well."
Karzai also emphasized the need for disarmament and a centralized control of the country if Afghanistan wants a stable future.