The suicide bomber rammed an explosive-laden car into the convoy in the northern Sayat district of Kapisa province.
A spokesman for the provincial governor said one foreign soldier and one civilian were also injured.
The spokesman also said a US military vehicle was destroyed in the attack.
US forces have declined to comment on the incident.
NATO-led forces said the nationality of the soldiers have not yet been released.
The troops deployed in Kapisa province are mainly US and French troops working under NATO command.
