Why are relations between Pakistan and Afghanistan so tense?

The Afghan Defence Ministry says it carried out several air strikes in Pakistan in retaliation for an attack last week. It's the latest act in growing cross-border violence between the neighbours. Pakistan says it was targeting armed groups along its frontier. But why are relations so tense right now? In this episode: Syed Akhtar Ali Shah, Former Secretary, Government of Khyber Pakhtunkhwa's Home & Tribal Affairs.  Obaidullah Baheer, Adjunct Lecturer, American University of Afghanistan. Kathy Gannon, Journalist and Former News Director, Associated Press for Afghanistan and Pakistan. Host: James Bays Connect with us:@AJEPodcasts on Twitter, Instagram, Facebook At Al Jazeera Podcasts, we want to hear from you, our listeners. So, please head to https://www.aljazeera.com/survey and tell us your thoughts about this show and other Al Jazeera podcasts. It only takes a few minutes!