One Afghan soldier has been killed, and two Pakistanis were wounded as Afghan and Pakistani troops exchanged fire along their border near Mohmand in Pakistan's north. Tensions between the two countries have escalated recently, with Afghan President Karzai accusing Pakistan of supporting the Afghan Taliban, and has ordered that any Pakistani installations within its territory be broken up. Pakistan has said it has nothing to do with armed groups that roam this border region. Al Jazeera's Imran Khan reports from Karachi.