More than 3,000 South Sudanese people have fled into neighbouring Uganda after government soldiers clashed with the opposing SPLA-IO in the border town of Pajok.
Witnesses say men, women and children were also victims in the attack. As the three-year civil war spreads across the world’s youngest nation there are increasing fears ethnic confrontation and reprisals against civilians.
South Sudan gained its independence from Sudan six years ago, but has been at war since December 2013.
The war was ignited by accusations from President Salva Kiir that his then-deputy Riek Machar was plotting to overthrow his government.
Machar denied the accusations but then went on to mobilize a rebel force to fight the government.
A peace deal signed in 2015 has continually been violated by both sides, with the United Nations last year warning of a possible genocide in the country.
The world body said in December that it had evidence of ethnic cleansing by both sides.
Machar is currently in South Africa where he flew to seek medical attention but has not been able to find an avenue back to South Sudan.