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.

South Sudan's conflict broke out Dec. 15 and has since killed thousands of people. An estimated half million people have been displaced.