Known by the acronym of UNMISS, the mission was created on July 8, 2011, on the eve of independence by the world's youngest nation.
UNMISS took over from UNMIS -- the United Nations' peacekeeping mission in Sudan before the south declared independence after six years of autonomy and decades of civil war.
Initially given a mandate of just one year, the UNMISS was charged with "consolidating peace and security" and setting in place "necessary conditions for development."
At first, it comprised some 7,000 soldiers and 900 police officers and experts, but the contingent was beefed up dramatically after civil war broke out in December 2013.
Six months later, the UN Security Council expanded the UNMISS mandate, authorising it to use "all means necessary" to ensure the protection of civilians, human rights and delivery of humanitarian aid.
The force now counts around 13,500 soldiers, making it the UN's third-largest peacekeeping mission today, after its deployments in the Democratic Republic of Congo and Sudan's troubled Darfur region.
At an emergency meeting on Sunday, the UN Security Council pressed neighbouring countries to help end the fighting and provide extra peacekeepers.
Its members also "expressed their readiness to consider enhancing UNMISS" so that the mission and the international community "can prevent and respond to violence."
UNMISS also runs six camps across South Sudan, housing about 170,000 displaced people.
The mission was criticised in February after a camp housing some 50,000 displaced people in the northeastern oil hub of Malakal was attacked by men in uniform in which at least 25 civilians were killed and 120 were injured.
The UN has launched an internal inquiry into the response of UN troops stationed at the camp.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)
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