Four people, including one security official, lost their lives on Saturday in a mine blast in Medan Valley of Khyber Agency.
Sources privy to the information said security forces were on a routine patrolling exercise in Medan Valley when a planted mine went off.
The blast resulted in the death of one security personnel and three civilians passing the area.
The security forces' vehicle was also damaged in the explosion.
Rescue teams and security forces arrived at the scene shortly after reports of the blast, security sources said.
The army had launched Operation Raddul Fasaad in February following a spate of terror attacks in the country, which claimed more than a hundred lives and left hundreds others injured.
The operation seeks to eliminate the "residual/latent threat of terrorism", consolidating the gains made in other military operations, and further ensuring the security of Pakistan's borders.
Hundreds of suspected terrorists have reportedly either been killed or arrested in raids carried out by security personnel since the start of the operation.