South Sudan has never conducted elections since becoming independent 10 years ago. A vote scheduled for 2015 could not take place due to the conflict that erupted in December 2013.

Last month, President Salva Kiir announced that elections would take place at the end of the transitional period in 2023.

But last week, First Vice-President Riek Machar warned against holding elections before a unified national army is formed.

President Kiir and Mr Machar formed a unity government in February last year to end conflict between their rival forces and agreed to form a unified army of 83,000 troops, a key part of the 2018 peace agreement they are yet to fulfil.

“We want to limit the possibility of violence – before the elections, during the elections and after the elections – if the parties choose not to accept the results," Unmiss head Nicholas Haysom told reporters in the capital, Juba, on Wednesday.

"I don’t think there is a golden script for the elections. It is really a decision for South Sudanese to decide under what conditions they want to conduct the elections,” Mr Haysom continued.

In March this year, the UN Security Council determined that the situation in South Sudan continued to constitute a threat to international peace and security in the region, and extended the mandate of Unmiss until 15 March 2022.

The resolution mandated Unmiss to advance a three-year strategic vision to prevent a return to civil war, build durable peace, and support inclusive, accountable governance and free, fair and peaceful elections.