Hagel was nowhere near the blasts, but heard them across the city. He told reporters traveling with him that he wasn't sure what it was when he heard the explosion.
"We're in a war zone. I've been in war, so shouldn't be surprised when a bomb goes off or there's an explosion," said Hagel, a Vietnam War veteran.
Asked what his message to the Taliban would be, he said that the US was going to continue to work with its allies to insure that the Afghan people have the ability to develop their own country and democracy.
Hagel's first visit to Kabul as Pentagon chief comes as the US and Afghanistan grapple with a number of disputes, from the aborted handover of a main detention facility — canceled at the last moment late Friday as a deal for the transfer broke down — to Afghan President Hamid Karzai's demand that US special operations forces withdraw from Wardak province just outside Kabul over allegations of abuse.
The prison transfer, originally slated for 2009, has been repeatedly delayed because of disputes between the US and Afghan governments about whether all detainees should have the right to a trial and who will have the ultimate authority over the release of prisoners the US considers a threat.