After more than 11 years of US-led military intervention in Afghanistan, the two countries are hammering out a deal to allow a limited US troop presence to remain when the international coalition leaves next year.
The size of the "residual" force has not been agreed, with numbers ranging from 2,500 to 12,000, according to US officials, as Washington winds down a war that has become deeply unpopular at home.
"We are in very serious and delicate negotiations with America," Karzai said. "America has got its demands, Afghanistan too has its own demands, and its own interests... They want nine bases across Afghanistan."
Karzai said he would allow bases in Kabul, Bagram, Mazar-i-Sharif, Jalalabad, Gardez, Kandahar, Helmand, Shindand and Herat if Afghanistan's security and economic conditions were met.
There was no immediate reaction from the US government.