Two United Nations peacekeepers were killed in an assault on their base in South Sudan along with 20 civilians who were sheltering there. They were the first U.N. casualties in a week of violence that has spread from the capital to energy-producing regions, spurring Beijing to move to evacuate some Chinese oil workers. What began Sunday night as a clash between army factions has spiraled into nationwide ethnic fighting that threatens to chase away foreign oil companies and choke the lifeblood of the fledgling nation’s economy. Some 500 people have been killed and more than 30,000 forced from their homes. Many civilians, including hundreds of oil workers, have sought shelter in bases belonging to the U.N. peacekeeping mission, which has reported fighting in six of the country’s 10 states. The U.N. said Friday that its base in the town of Akobo, in Jonglei state, had been attacked overnight “by […]