Militants also wounded eight people when they fired rockets and automatic rifles at Karzai and other dignitaries during a ceremony Sunday in Kabul to mark the mujahedeen victory over the Soviet occupation of Afghanistan.
The Taliban claimed responsibility. Three of the attackers were killed, the government said, but the Taliban said additional attackers were involved.
Less than two hours after the attack, Karzai appeared on state-run television and said "everything is OK."
"Today, the enemies of Afghanistan, the enemies of Afghanistan's security and progress tried to disrupt the ceremony and cause disorder and terror," Karzai said, according to Reuters. "Afghanistan's military forces surrounded them quickly and arrested some of the suspects."
The gunfire apparently came from a three-story guesthouse about 300 yards from the stands where Karzai was seated alongside Cabinet ministers and senior diplomats, who all escaped unharmed.
Residents said a 30-minute gun-battle broke out between security forces and gunmen holed up in the guesthouse.
Taliban spokesman Zabiullah Mujaheed said six militants were sent to target the president, and three them died. He said they were armed with guns, rockets and suicide vests although no suicide bombings were reported.
"Thankfully, President Karzai was not harmed," White House press secretary Dana Perino said Monday.
"The terrorist threat is real, it is deadly, and defeating this enemy has to be a top priority of the United States, of the Afghan government, of the Iraqi government, and the NATO alliance," Perino said.
About 100 people were rounded up for questioning, an Afghan intelligence official said on condition of anonymity because he was not authorized to speak to media. Some of those detained have since been freed, said Defense Ministry spokesman Gen. Mohammad Zahir Azimi.
Karzai has escaped several assassination attempts. His narrowest escape came in September 2002 when a gunman opened fire at close quarters as he visited the southern city of Kandahar. Three people, including the gunman, died in that attack.
On Sunday in eastern Afghanistan, the U.S. military said it and Afghan troops managed to fight off coordinated insurgent attacks on five military outposts. Dozen militants were killed in the fighting and a dozen more wounded, the military said. No U.S. or Afghan soldiers were hurt.
