BEIRUT, Sept. 9 (Xinhua) -- Four people were killed when a group of gunmen attempted to rob a mobile shop and exchanged fire with its owners in Lebanon's northern city of Tripoli on Friday evening, Al-Jadeed TV channel reported. The exchange of fire inside the shop killed one of the gunmen, the shop owner and two of his friends, the report said, adding the gunmen carrying machine guns and hand grenades had fled the scene. The Lebanese troops were immediately deployed in the area and started to hunt the attackers through surveillance cameras. Lebanon has been facing a deep financial...