Kabul: A suicide bomber struck a bus carrying security personnel in Afghanistan's capital Kabul on Monday, officials said. "The attack took place in Pul-e-Charkhi road. There is fear of possible casualties," an official told Xinhua news agency. "So far, we have no more details, but we will try to get more information," the official added. Witnesses said they heard heavy explosion when the attacker targeted the bus carrying foreign security guards presumably from Nepal.