A foreign journalist was Tuesday roughed up by an angry mob as she covered a demonstration against the American arms embargo in Juba.
The demonstration was organised by various youth groups, including the Sudan People Liberation Movement (SPLM) Youth League.
The incident happened at the UN mission main camp near the Juba International Airport.
A local journalist who witnessed the incident said the irate youths seemed to be angry at mostly foreign nationals.
The mob also beat up a local journalist working for the Juba-based radio station.
The South Sudan government was yet to issue a statement on the incident.
The US last Friday announced a ban on arms sale to South Sudan, saying the continuing violence, which has created one of Africa's worst humanitarian crises, showed no signs of ending.
It also said both the government and rebels were heavily spending on military than on peace and development.
Juba reacted angrily to the US action and summoned its ambassador to Washington, Mr Garang Diing Akuong, back home.
Human Rights Watch (HRW) welcomed the US arms ban, saying it would send a strong signal to the South Sudan leaders that abuses and broken promises would not be tolerated.
CORRECTION: The journalist roughed up in South Sudan demo was not American and she was not critically injured as stated in the earlier version of this story.