The formation of a unified national army is a “critical element” in South Sudan’s transition to peace, head of the UN peacekeeping Mission in South Sudan (UNMISS) Nicolas Haysom has said.

Mr Haysom told the UN Security Council in New York that the overall implementation of the September 2018 revitalised peace agreement was "progressing slowly".

He said on Monday that the formation and graduation of troops for the unified forces that was critical to prevent a relapse to conflict was "behind schedule".

"Troops continue to suffer in cantonment sites without adequate shelter, healthcare, and food. It is therefore important that precondition of a coherent command and control structure is finalised, followed by the graduation of forces," Mr Haysom said.

He reported that inter-communal violence continues to cause insecurity and obstructs the realisation of a durable and sustainable peace in South Sudan.

Mr Haysom also told the Council that this year, more than 80% of civilian casualties were attributed to inter-communal violence and community-based militias.

"Nevertheless, weak or absence of state governance institutions throughout South Sudan have enabled spoilers to exploit perennial communal and ethnic cleavages. Entranced insecurity has hindered the cultivation of crops and has contributed to a vicious cycle of livestock raiding. Many communities are dangerously short of food supplies," he said.

President Salva Kiir and his former arch rival Riek Machar, now First Vice-President, formed a unity government in February last year, but the country still faces major challenges including – the formation and graduation of a unified national army – made up of 83,000 forces.