The attack took place in a remote area of the valley and the wounded were being transported to a hospital in the region, said officials.
Peshawar: A Pakistani government official says a roadside bomb has killed at least five people and wounded several others in a northwest tribal region close to the Afghan border.
Mohammad Iqbal Khan says the remote controlled bomb was detonated on Monday in Tirah valley in the Khyber tribal region as volunteers from a government-backed militia were moving into the area.
Khan said the attack took place in a remote area of the valley and the wounded were being transported to a hospital in the region.
No group has immediately claimed responsibility but Islamic State group militants have been responsible for previous similar attacks. Pakistan's army is battling militants in tribal regions bordering Afghanistan.