Juba: The president of South Sudan has replaced army chief Paul Malong, state media said on Tuesday, after a slew of resignations by senior generals alleging ethnic bias and war crimes.

President Salva Kiir has appointed General James Ajong as the new army chief, the South Sudan Broadcasting Corporation reported, citing a presidential decree. The report did not say why Kiir had replaced Malong or give further details.

South Sudan, the world's youngest nation, has been mired in civil war since 2013 when Kiir, an ethnic Dinka, fired his deputy, Riek Machar, a Nuer.

The move triggered a conflict that has plunged parts of the oil producing country into famine, paralysed public services and forced 3 million people - a quarter of the population - to flee their homes. The United Nations has said the violence amounts to ethnic cleansing and risks setting the stage for genocide.

In February, the head of logistics, Thomas Cirillo Swaka, resigned, citing rampant human rights abuses by the military and the dominance of the president's Dinka ethnic group.

His announcement brought a wave of other resignations by generals and civil servants who made similar accusations against the government.