Osama bin Laden could hide more easily in a city than a remote tribal region, a former Pakistani intelligence chief said on Tuesday, challenging the notion that the al-Qaeda leader is probably holed up in a mountain cave. Lieutenant-General Asad Durrani, former head of the powerful Inter-Services Intelligence agency (ISI), said news of outsiders' presence travels fast in the tribal areas and it would be hard to keep it secret for years. “In the countryside or in tribal areas it’s difficult to hide yourself because people live there and operate in a manner in which finding out about unusual presence is very important,” Durrani told Reuters in an interview in London.