Two Frontier Constabulary soldiers were injured in cross-border firing in Kurram Agency from Afghanistan's Khost province on Friday, security sources said.

The attack took place as FC personnel were undertaking construction of a wall along the border on the Pakistani side, the sources said, adding that they returned fire across the border.

This is the second cross-border attack coming from Afghanistan over the past week. At least 12 people were killed and over 40 others injured as Afghan border forces opened fire on security personnel guarding a census team in Balochistan's Chaman area last Friday.

On Sunday, Inspector General Frontier Corps Balochistan Maj Gen Nadeem Anjum claimed that 50 Afghan security personnel were killed and another 100 injured as Pakistani forces retaliated to the unprovoked attack.

The claims were, however, denied by Afghanistan's Ambassador to Pakistan Omar Zakhilwal who said that only two Afghan soldiers were slain and seven others injured.

Both sides have called for peace in the aftermath of the attack, with Adviser to the Prime Minister on Foreign Affairs Sartaj Aziz saying that Afghanistan had been asked to use diplomatic channels to resolve issues with Pakistan "instead of bullets".

During hotline contact after the cross-border attack last week, the Afghan director general of military operations admitted his side’s mistake in identifying the boundary in the area and acknowledged that the international border lies between the villages and not at a ditch, as perceived by them, according to the army's media wing.

Following confusion over geography, both sides conducted a survey of the Killi Jahangir and Killi Luqman villages to dispel of discrepancies in maps.