South Sudan crisis explained - in 60 seconds
7 January 2014 Last updated at 10:48 GMT
At least 1,000 people are believed to have died in clashes in South Sudan between rival army factions - in a conflict escalated by ethnic undertones.
President Salva Kiir says the violence started after a coup attempt, blaming soldiers loyal to former Vice-President Riek Machar for the trouble. Mr Machar denies this.
The BBC outlines the background to the crisis - in 60 seconds.
Video produced by Michael Hirst