The announcement, which comes more than two years into the country's brutal war, marks the latest move by the RSF to establish parallel governance, in defiance of the army-led administration.

Sudan is split, with the army controlling the north, east and centre, having recently retaken the capital Khartoum, while the RSF holds most of Darfur and parts of Kordofan, where recent attacks have killed hundreds, according to local rights groups.

The internationally-recognised army-aligned government, formed in May and headed by former UN official Kamil Idris, remains incomplete, with three cabinet positions still unfilled.

Analysts have warned the RSF's formation of a parallel government could deepen Sudan's fragmentation and complicate diplomatic efforts to end the conflict that began in April 2023.

On Saturday, coalition spokesperson Alaa El-Din Naqqad announced that Mohamed Hassan al-Ta'ayshi -- who served on the transitional Sovereign Council from 2019 until the 2021 military coup -- had been appointed head of what the RSF calls the "government of peace and unity".

An RSF member told AFP on condition of anonymity that al-Ta'ayshi will form the new cabinet.

The RSF-led coalition also unveiled a 15-member presidential council, with RSF commander Mohamed Hamdan Dagalo as president and rebel leader Abdelaziz al-Hilu -- who controls parts of southern Sudan -- as vice president.

The council also includes political figures, ex-officials and newly appointed regional governors.

Among the appointees is El-Hadi Idris, named governor of Darfur -- a region that now has two rival governors, one appointed by the RSF and the other, Minni Arko Minawi, aligned with the army.

The appointment of a prime minister follows a political charter signed in February between the RSF and its allied armed and civilian groups during talks in Nairobi.

There was no immediate response from the army on the RSF's new prime minister appointment.

The war began after a power struggle between army chief Abdel Fattah al-Burhan and Dagalo -- once allies who ousted Omar al-Bashir in 2019, then staged a joint coup in 2021.

The United Nations repeatedly said that Sudan now faces one of the world's worst humanitarian crises.

In addition to the tens of thousands killed, millions have fled their homes and basic services -- from healthcare to water -- have collapsed across much of the country.