An ambulance rushes to the scene of a suicide bomb attack in the Afghan capital.
The morning rush hour blast targeted a convoy of vehicles carrying foreign troops through Kabul.
At least 6 Afghan civilians were killed. It was not clear if any foreign forces were killed or wounded.
The Hezb-e-Islami insurgent group, allied with the Taliban, claimed responsibility for the attack, telling Reuters that U.S. military advisors were the targets.
NATO's International Security Assistance Force said it was aware of an explosion and was looking into reports of ISAF casualties.
Hezb-e-Islami is a radical militant group which shares some of the anti-foreigner, anti-government aims of the Taliban.
The group killed seven South African and Russian pilots in a bomb attack in Kabul last year.
