Twenty-eight others were hurt when the convoy was hit in the remote tribal region of North Waziristan.
A spokesman acknowledged the attack could be linked to the storming of the Red Mosque earlier this week.
Troops have been sent close to the area amid fears fighters may be planning a "holy war" in response to the siege.
The 102 people killed in the week-long siege included 11 soldiers and an as yet unknown number of extremists and their hostages.
The government's operation against the radical Islamists sparked protests across Pakistan
In the north-western city of Peshawar on Friday more than 1,000 demonstrators vowed to avenge the death of the mosque's deputy leader, Abdul Rashid Ghazi.
North Waziristan, near the Afghanistan border, is often the scene of clashes between troops and tribesmen or foreign militants.
Army spokesman Maj-Gen Waheed Arshad said the wounded from Saturday's incident were being taken to hospital after the attack near the village of Daznary, about 50km (30 miles) north of Miranshah.
A search is still under way for one missing vehicle after the convoy was struck by the attacker's explosives-laden vehicle.
In a second attack on Saturday, two security officials were hurt in a blast near the town of Bannu in North-West Frontier Province.
Thousands of troops have been moved into the province as President Pervez Musharraf vows to pursue his campaign of rooting out extremists.
Although there is no new deployment to Waziristan, fighters there say the government has broken peace agreements by setting up checkpoints.
Commander Abdullah Farhad told the Agence France-Presse news agency there could be "guerrilla war" if all checkpoints were not removed by Sunday.
Protests against the Red Mosque attack were held across the country on Friday.
Demonstrators in Peshawar were told it was a "genocide" in which "hundreds of innocent women and children died".
In Islamabad, hundreds of demonstrators attended a rally organised by Pakistan's main alliance of radical parties, the Muttahida Majlis-e-Amal.
"This carnage will prove to be the last nail in the coffin of Musharraf's dictatorial rule in Pakistan," the group's deputy leader Maulana Abdul Ghafoor Hydri told the gathering.
"Now there will be Red Mosques everywhere in Pakistan."