The Office of the United Nations High Commissioner for Refugees (UNHCR) has warned of the rising number of people forced to flee from their homes in South Sudan, with more than 700,000 refugees expected by the end of the year.

Speaking at a news briefing on Friday, UNHCR spokesperson Melissa Fleming raised the alarm over the deepening humanitarian crisis in South Sudan as clashes rage on between pro-government forces and rebels in the country.

“The ongoing conflict … inside the world’s youngest nation is fuelling a refugee exodus into Ethiopia, Kenya, Sudan and Uganda at a much higher rate than initially anticipated,” Fleming said, adding, “The figure of 715,000 more than doubles the number of refugees envisaged” when the UN’s refugee agency began a funding appeal for the South Sudanese refugees four months ago.

Meanwhile, the agency revised its funding appeal to USD 658 million from the original USD 371 million requested in March.

It also noted that Ethiopia is witnessing the biggest surge in refugee arrivals, with over 1,000 refugees a day crossing into the town of Burubiey.

The development came on the same day that the charity Save the Children warned that over 2,600 people have been infected with and 60 killed by cholera in South Sudan since its first cases were detected in the capital Juba in May.

South Sudan plunged into violence in December 2013, when fighting erupted between troops loyal to President Salva Kiir and defectors led by his sacked deputy, Riek Machar.

The conflict soon turned into an all-out war between the army and defectors, with the violence taking on an ethnic dimension that pitted the president’s Dinka tribe against Machar’s Nuer ethnic group.

Thousands of people have so far been killed in the war. The fighting has reduced significantly since the latest ceasefire deal was signed on June 10, but the talks being held in Ethiopia’s capital Addis Ababa between the two warring sides have stalled.