The incident took place in Qamaruddin Karez area of Zhob district along the Pak-Afghan border in the morning.
"The indiscriminate firing opened by Afghan security forces left five tribesmen of 'Loion' tribe dead," official sources said, adding that the three injured included a Levies Force personnel.
The Afghan Charge d' Affaires was summoned to the Foreign Office and a strong protest was lodged over the "indiscriminate firing today by the Afghan Border Police" in Zhob district near the Pak-Afghan border, an official statement said.
The Afghan Government was asked to hold an inquiry into the incident, adhere to the border coordination and cooperation mechanisms and prevent the recurrence of such incidents which are detrimental to the friendly relations and undermine goodwill between the two brotherly countries, the statement said.
A district administration officer said the cause behind the firing could not be ascertained, however, it was sheer violation of security of Pakistani borders as the Afghan security forces personnel opened fire without any provocation.