One person was injured when the rockets landed near a produce market, CNN reported.
Security is extremely tight around the national assembly, or loya jirga, called to address the future of NATO and the U.S. military in Afghanistan. Troops lined the roads outside the loya jirga tent near the Intercontinental Hotel amid fears of a Taliban attack, CNN said.
Kabul police said security forces killed a suicide bomber Monday near the meeting site. He was wearing a suit and carrying a briefcase when he was stopped.
Karzai, in a speech Wednesday before the national assembly, said Afghanistan needs a long-term security pact with the United States that respects Afghan sovereignty.
"We want our national sovereignty, and an end to night raids and to the detention of our countrymen," he said. "America is powerful, has more money, but we are lions here. Lions have the habit of not liking strangers getting into their house."
CNN said the loya jirga is considered an important step toward a possible peace deal with insurgents.