Pakistani troops have come under sustained attacks in the past two days. At Swat, North West Frontier Province, a convoy was hit by a double suicide car bomb blast.
More than a dozen people died in Sunday's attack in the village of Matta.
It was one of at least three such attacks targeting security forces that have killed more than 50 in the last two days alone.
On Saturday, a suicide attack on a convoy near Miranshah in North Waziristan killed 24 people and injured 30.
Locals there began fleeing the area.
The restive region is bracing for more violence as militants ended a ceasefire with the government.
The army has deployed thousands more troops to the NWFP in anticipation of a new "holy war".
Officials fear the week-long Red Mosque siege, which led to more than 100 deaths, is sparking militant reprisals.