A gunman has killed two foreign workers with the Doctors without Borders after he opened fire on them at the aid group's office in Somalia's war-torn capital Mogadishu, Press TV reports. A Somali security official, speaking on condition of anonymity, told Press TV that the incident took place on Thursday evening as a Somali man wielding a gun attacked the aid workers near a busy junction in Mogadishu, and shot them dead. "One died straight away, another was seriously wounded and died soon after,” a witness said. There are reports that the assailant, who earlier worked as a logistics officer for Doctors without Borders, had been dismissed from his job a day earlier. He returned on Thursday and opened fire, killing the two aid workers. A resident of a refugee camp shot and killed three aid workers in central Somalia on December 23, including two workers with the United Nation's World Food Programme. The attack took place in town of Matabaan, which is located about 30 kilometers (20 miles) from the Ethiopian border in Somalia's central Hiran region. The three Somalis were shot and killed as they returned from a camp for families displaced by violence and famine. Somalia has not had a functioning government since 1991, when warlords overthrew former dictator Mohamed Siad Barre. Strategically located in the Horn of Africa, Somalia remains one of the countries generating the highest number of refugees and internally displaced persons in the world.