The Taliban claimed responsibility for the blast, which came a day after a statement claimed responsibility for a suicide attack outside a military training academy that killed at least six people.
A US military spokesman in Afghanistan said a car bomb wounded a US convoy and wounded four service personnel, but did not give further details.
However, there were conflicting reports on the total number of casualties caused by the blast.
An Afghan security official, speaking on condition of anonymity because he was not authorized to speak publicly, said up to 9 people were killed and six civilians injured in the blast.
The Taliban's main spokesman, Zabihullah Mujahid, said in a statement that the attack targeted a convoy of foreign troops, killing 10 of them and the destruction of two cars.
The photos, posted on social media, showed a heavily damaged white-armored Land Cruiser, a type commonly used by international organizations, surrounded by firefighters.