Pakistan, worried by Islamist attacks, is building a fence to prevent militants criss-crossing the porous 2,500 km (1,500 mile) frontier along the disputed colonial-era Durand line drawn up by the British in 1893.
Thousands of Pashtun tribal people who for decades ignored the invisible line that bisects their dusty villages and demarcates the Afghanistan-Pakistan frontier are bracing for a Berlin Wall-style divide of their neighbourhoods.
The fence, which Kabul opposes, will run down the middle of so-called "divided villages" where few people have passports and Pashtun tribal loyalty often trumps allegiance to the state.
Seven such villages are dotted around Chaman district, home to the bustling border-crossing town of Chaman in Pakistan's southwestern province of Baluchistan. Other divided villages are believed to exist further north in the restive Federally Administered Tribal Areas (FATA).
Pakistani officials in Baluchistan are now working on shifting Pakistani citizens in the divided villages to their side of the fence and say security worries override concerns that it will break up communities.
"(A border wall) was there in Germany, it is in Mexico. It is all over the world – why not in Afghanistan and Pakistan?" said Col. Muhammad Usman, commander of Pakistan's Frontier Corps paramilitary force in Chaman.
"These tribals have to understand that this is Pakistan and that place is Afghanistan."
Yet scepticism about the fence abounds. Pakistan's previous attempts to build one failed about a decade ago and many doubt whether its possible to secure such a lengthy border.
