Ten medical aid volunteers were killed in one Afghanistan attack in August. In July, a 78-year-old French humanitarian worker was executed along the Mali-Mauritanian border after some three months in captivity. (..) Another aid worker, Marcus Prior, 41, with the U.N.'s World Food Programme (WFP), spoke to CNN via phone from WFP's offices in Islamabad, Pakistan's capital, where he was getting a quick break from working in the flooded Swat Valley.(..) "Places like Somalia and (the Democratic Republic of the) Congo have been particularly dicey at times," he said. "I remember on one of my very first aid missions to Somalia, being rushed into our office because there was an unidentified gunman in the vicinity.