The blast exploded when the security forces convoy was on its way to Kurram Agency.
At least four security personnel were killed while eleven others injured in an attack on their convoy in Hangu.
According to security sources, a roadside bomb exploded when a convoy of security forces was passing through Warmagai, killing four soldiers on spot while injuring eleven others.
The injured and the dead were immediately taken to CMH. It is feared that the death toll may also rise, the sources added.
Meanwhile, the security forces cordoned off the area soon after the blast. A search operation is underway.