President Asif Ali Zardari was due in Kabul on Tuesday for his first official visit to Afghanistan, which was likely to focus on how to tackle extremist violence straddling the common border. Zardari, who postponed a trip last month because of bad weather, is due to meet Afghan President Hamid Karzai shortly after arriving from Islamabad, the Pakistani embassy said. "They will mainly be discussing bilateral relations, economic cooperation, trade and the regional situation," embassy spokesman Naeem Khan told reporters.