About three NATO soldiers and two civilian contractors were killed Saturday in a blast in southern Afghanistan, officials said.NATO-led International Security Assistance Forces (ISAF) said in a statement that three of its soldiers and two “coalition civilians” were killed in a “improvised explosive device” or roadside bombing. The statement did not give further details on the identities of the casualties or the location.In a separate incident in southern Afghanistan, a pedestrian was killed after a suicide bomber rammed his vehicle into a convoy belonging to a provincial governor.Governor Mohammad Ashraf Nasiri escaped unhurt in the attack that also injured two of his guards, Deputy Governor Mahammad Jan Rasolyar.The bombing took place in Qalat, the provincial capital of Zabul province, as the governor left with senior officials to an event at a local school, his office said