The U.S. military in Africa says it has sent 40 additional soldiers to South Sudan's capital, Juba, to help secure American personnel and facilities in the war-torn city.

Renewed fighting between opposing army forces has raised fears of a return to civil war in South Sudan. Here's a look at the what brought on the tense situation.

The president of South Sudan declared a unilateral cease-fire Monday to a conflict that has seen fierce clashes between his army and opposition forces spread from the capital to a southeastern town.