More than a million people have been displaced by fighting between rival political groups in South Sudan.
Aid groups are warning that thousands are now facing food shortages.
Relations between Juba and the United Nations mission were strained after weapons were seized from UN-hired vehicles last month.
The instability has also put the country's planting season at risk, raising fears that a lack of crops will further deteriorate the situation.
Al Jazeera's Osama Bin Javaid reports.