South Sudan is ending the year on an inauspicious note, with fears of civil war running high. The speed with which violence has spread across the country in a couple of weeks is an alarming reminder that the nation that emerged independent from Sudan in 2011 after years of conflict has a tenuous hold on the future.

Within days of clashes on Dec. 15 between rival factions of government and military leaders, the United Nations and human rights officials have reported hundreds of civilians killed in attacks in the capital and other cities. About 81,000 residents, a figure considered a conservative estimate, have been displaced by fighting in several of South Sudanís 10 states. U.N. peacekeeping bases have been overwhelmed by tens of thousands of civilians seeking refuge.

The ugly convulsion in South Sudan brings to the fore yet again the fault lines that lie beneath the tragedies that have beset nation-building efforts in many African countries. Frequently, it falls to political rivals with deep, often-hostile ethnic loyalties to govern fairly and efficiently, to share political power and scant national resources in an open and democratic process.

Too often, as in South Sudan, the leaders have failed at the task, the fallout ensnaring the innocent. In what appears to be a struggle to consolidate power, the government led by President Salva Kiir, a member of the dominant Dinka ethnic group, is fighting loyalists of the former vice president, Reik Marchar, an ethnic Nuer whom Kiir fired in July and has accused of attempting a coup. As U.N. representatives report, the violence triggered by rivalry at the top has followed ethnic divisions, Nuer and Dinka citizens bearing the brunt of the hostilities in various states.

The upheaval is creating an emergency for shelter, food and water and health care in this poor country. Further, the killings raise the specter of a vicious civil war, one more disaster Africa can ill afford. In a bid to halt the spiral of killings, the U.N. has doubled its peacekeeping and police force. Leaders in neighboring countries are urging Kiir and Marchar to negotiate a settlement. For the new country, anything less will be a betrayal of the hope for peace, stability and economic development.