A convoy of security forces was travelling from Hangu to Kurram tribal area when it was targeted near Warmagal on the Hangu-Kurram border.
Three soldiers were killed whereas 11 others sustained injuries. One soldier later died of his injuries.
Sources said the vehicle the soldiers were travelling in was also damaged in the attack.
They said the blast was carried out using an Improvised Explosive Device (IED) and might have been detonated through a remote control.