In a press release issued on Thursday, the Mission expressed deep concern over the violence and loss of life that occurred in Wau, Western Bahr El Ghazal State, on December 8 and 9 2012.
The release also called on the authorities to take prompt action to prevent an escalation of violence and to seek accountability if disproportionate force has been used during demonstrations.
UNMISS called on all parties and the civilian population to remain calm and respect the rule of law.
The release said nine civilians have been confirmed killed and many more injured in incidents involving demonstrators and members of the security forces.
And that the recent escalating tensions, the incidents of violence, and attacks on property are of great concern.
The released explained that UNMISS is investigating the use of force and other reports of violence in order to establish the facts behind these tragic events.
The Mission is offering assistance to the Government of South Sudan and the State authorities.