South Sudan's rival leaders have, once again, missed a key deadline to form a transitional unity government, raising new concerns for a fragile peace process in a country devastated by years of ruinous civil war.President Salva Kiir and rebel leader Riek Machar had agreed in September to create a power-sharing government by Tuesday.READ | South Sudan rival leaders agree to 100-day delay to form unity government - ministerBut at a meeting last week mediated by Ugandan President Yoweri Museveni and Sudan's interim leader Abdel Fattah al-Burhan, the two leaders agreed to push back by 100 days the formation of the new administration.The talks in Entebbe, Uganda, noted that "critical tasks" were still not completed, including issues related to security arrangements, governance and the integration of fighting forces.It is the second time that an extension has been granted following the signing last year of the latest peace deal between warring sides amid pressure to end the years-long conflict that has killed hundreds of thousands of people and displaced millions of others.DisputesSigned in the Ethiopian capital, Addis Ababa, in September 2018, the Revitalised Agreement on the Resolution of the Conflict in South Sudan provided for the rebels to join the transitional government and the settling of a number of disputes, including the number of regional states the country should have and their boundaries.As part of the agreement, which ushered in a ceasefire, forces from the warring sides were also meant to be registered and merged to form a national army of more than 80 000 soldiers, which was supposed to be followed by Machar's return from exile.While the integration of the forces has not happened, the rebels have accused Kiir's government of failing to disburse the $100m it had pledged for the implementation of the deal."It is well documented the economic challenges we are facing. We are committed to paying the agreed sum. So far, we have contributed almost $30 million of the agreed $100 million," said Ateny Wek Ateny, Kiir's spokesperson.In December 2015, two years after the conflict broke out and months after the signing of another peace deal, Kiir increased the number of states in the world's youngest country from 10 to 28.The controversial move angered the rebels, with the number of states and their internal boundaries remaining a sticking point until today."The president increased the number of states following demands from our people to do so," Ateny said. "The government is happy to revisit that decision if our people demand it. It is not just up to the president and the opposition leader to decide. Discussions are currently ongoing to find a lasting solution to this."