What should one country do if it is having problems with its neighbor who's a potential source of trouble, too? Build a wall between their borders, of course.
That's the solution Pakistan is pursuing as it has started building a fence on its border with Afghanistan. On the other hand, the move can further anger Afghanistan and worsen already tense relations between the two countries. Pakistan and Afghanistan both accuse each other of harboring terrorists.
Afghanistan does not recognize Pakistan's hundred of miles of mountainous northwest border, drawn up under the past British colonial rule. Pakistan closed the border for more than a month starting in February for security reasons. Afghanistan protested the move that Pakistan decided to reopen it would on March 20.
Rebels from Pakistan have moved to Afghanistan and have staged their attacks against their original country from Afghanistan. On the other hand, Afghanistan has been accusing Pakistan of providing shelter to the militant and radical Afghan Taliban and the allied Haqfani network. The U.S. also shares Afghanistan's concerns on Pakistan harboring the Afghan Taliban group.
The Pakistani army believes that building a wall along their borders with Afghanistan will be both good for the neighbors. They believe that a better managed, secure and peaceful border will help both countries fight terrorism better.
Pakistan is still recovering from a recent series of terrorist attacks that killed more than a hundred of its people across the country. The attacks includes a suicide bombing in February at a shrine that killed dozens of people. Pakistan blamed the attacks on rebels who are based in Afghanistan.
Afghanistan is not in favor of building a wall between them. The government believes a wall will not help solve the problems between them and their neighbor, but would only worsen the relations between the two countries. The Afghanistan military is instead challenging Pakistan to fight terrorism by not providing "sanctuaries" to terrorists, by stopping to fund train and help them.
The U.S. for its part has always accused the Pakistan military of supporting the Taliban. Pakistan has always denied the charge but at times admitted the presence of Afghan Taliban on its territory.
Both Afghanistan and the U.S.-led coalition troops also know the presence of Pakistani rebels in Afghanistan. Pentagon said that a U.S. airstrike earlier this March had killed Pakistani rebel Qari Yasin. The U.S. commander in Afghanistan who says the security situation there has reached a stalemate is asking the administration of President Donald Trump to send thousands of additional troops there.