Officials say at least nine civilians have been killed in a suicide-bomb attack outside the Afghan Defense Ministry in central Kabul.
The blast on March 9 occurred during a visit to Afghanistan by new U.S. Defense Secretary Chuck Hagel.
Officials said Hagel was not near the explosion and was unharmed.
Officials said the bomber arrived at the Defense Ministry on a bicycle.
The attack has been claimed by the Taliban.
Taliban spokesman Zabiullah Mujahid said the attack was not meant to target Hagel, but to send the message that the militants are capable of striking in Kabul even during a visit by the top U.S. defense official.
A statement from the NATO-led International Security Assistance Force (ISAF) said the blast was followed by small-arms fire.
Pentagon spokesman George Little said Hagel was attending a briefing at a U.S.-led military coalition facility in another part of Kabul when the explosion occurred. He said the briefing continued without interruption.
'Dangerous And Difficult'
As he opened his surprise visit on March 8, Hagel said U.S. and NATO-led troops are “still at war” in Afghanistan.
He said the mission to counter Taliban and Islamist extremist militants remains “dangerous and difficult,” but said the goal of helping Afghan forces take full security responsibility is “clear and achievable.”
Hagel said he would meet President Hamid Karzai during his visit, which he said was aimed at learning more about the situation in Afghanistan.
"I need to better understand what's going on there. I need to talk to, listen to, get a good sense from our commanders on the ground," Hagel said.
Hagel said he planned to speak with Karzai about the recent decree expelling U.S. special forces from Wardak Province. Hagel did not say what his message to Karzai would be.
Karzai ordered U.S. commandos to leave the province within two weeks because of allegations that Afghans working with them were involved in abuse and torture.
Hagel was sworn in to office less than two weeks ago, on February 27.
Some 66,000 U.S. troops and 30,000 from NATO and other allied forces are still based in Afghanistan. But many of these forces are planned to start leaving this year, ahead of a full withdrawal of foreign combat forces at the end of 2014.
Based on reporting by Reuters, AFP, and AP