The convoy of military vehicles was travelling from Datakhel to Miramshah when it was struck by a remotely-detonated bomb in Boya area of North Waziristan tribal region.
At least nine soldiers died and nine others were wounded in the explosion, Dawn reported.
The victims were shifted to the Combined Military Hospital.
A military statement had earlier put the figure at three.
A daily curfew is imposed in the area from 4 pm evening till 5 am in the morning ensure safe passage for the movement of military personnel.