More than 10 per cent of South Sudan's 11.3 million people have fled the country in a mass exodus that was now accelerating, the United Nations reports.
In addition to the nearly 1.3 million South Sudanese living in refugee camps, about 1.6 million more have been displaced inside the country, the UN says. Some 200,000 were sheltering in or near UN peacekeepers' bases.
About 40 per cent of South Sudan's remaining inhabitants were facing impending famine, the UN's food agencies warn.
At least five simultaneous disease outbreaks were threatening lives as well, international health specialists say.
Malaria, measles, cholera, guinea worm and kala azar (a parasitic killer) were all spreading amidst a breakdown in sanitation and health care resulting from the three-year-long civil war.
At the same time, “there is a strong risk of violence escalating along ethnic lines with potential for genocide," Mr Adama Dieng, the UN special advisor on preventing genocide, declared on Friday at the conclusion of a five-day visit to South Sudan.
“Throughout the week, conversations with all actors have confirmed that what began as a political conflict has transformed into what could become an outright ethnic war,” he added.
Close to 6,000 people fleeing these conditions entered Uganda on a single day earlier this month, bringing the total number of South Sudanese refugees in that neighbouring country to over half a million.
“The current extremely high sustained trend of arrivals is expected to continue, and puts pressure on all aspects of the response, which is currently very under-resourced,” the UN refugee agency said in an update last week.
Another 323,000 South Sudanese refugees have gone to Ethiopia, with about 600 arriving on average each day.
Life was so difficult in South Sudan that more than a quarter-million of its citizens had sought refuge in Sudan, the country from which it separated five years ago. Many of the refugees have crossed into Sudan's Darfur region, where war has been raging for 13 years.
Similarly, about 60,000 South Sudanese have fled to eastern Democratic Republic of Congo, the site of fighting that has taken tens of thousands of lives in recent years.
Kenya has received 90,000 South Sudanese refugees, and 5,000 have moved into Central African Republic, where another civil war continues sporadically.
A plea for $251 million in donor funding for South Sudanese refugee assistance has drawn a tepid response. Less than $50 million has been received “despite the rapidly growing need,” the UN refugee agency says.