The bomb was triggered by remote control as the convoy was passing through a market in Bara, the main town in the lawless Khyber Agency that borders Afghanistan. The blast hit two vehicles.
A captain was among the dead, officials of the local political administration said.
The convoy of the Frontier Corps was coming to Bara from Peshawar, the capital of Khyber-Pakhtunkhwa province. The injured were taken to a military hospital in Peshawar.
Security forces cordoned off the area and started a search operation.
No group claimed responsibility for the attack.
The banned Tehrik-e-Taliban Pakistan and al Qaeda-linked militants have strongholds in Khyber Agency.
