Three cases involve the International Organization for Migration (IOM) and one the United Nations Children's Fund (UNICEF).
Foreign Ministry advises Israelis to avoid country on brink of civil war.
The struggling, war-torn country of South Sudan was one of the east African countries that Netanyahu spoke about during his trip to Africa last week as having an interest in closer ties with Israel.
The attack took place on Friday in the Horn of Africa nation's Gambela region.
Fund seeks to raise $60,000 for generator at orphanage.