The suicide bomber rammed an explosives-laden vehicle into Esha check post near Miranshah, the main town of North Waziristan Agency, last night.
Six security personnel were killed instantly and 11 more died later.
Over a dozen security personnel were injured, officials said earlier.
Troops cordoned off the area after the attack and launched a search operation. Authorities imposed a curfew in the region.
No group claimed responsibility for the suicide attack.