Leaders of the Sudan Revolutionary Front (SRF), an umbrella organisation of rebel groups from the western region of Darfur and the southern states of South Kordofan and Blue Nile, raised their fists in celebration after inking the agreement.

The deal was "initialled" and not signed, as a way to leave the door open for two key holdout rebel groups to join in a "final" agreement, officials said.

Two rebel factions have refused to take part in the deal.

Eager to celebrate the most tangible success since last year's fall of longtime dictator Omar al-Bashir and the establishment of an uneasy transitional government, officials met in the capital of neighbouring South Sudan.

Forging peace with rebels has been a cornerstone of Sudan's transitional government, which came to power in the months after the overthrow of Bashir in April 2019.

Sudan's government, led militarily by General Abdel Fattah al-Burhan, head of a sovereign council, and on the civilian side by Prime Minister Abdalla Hamdok, says it views peace-building as the cornerstone for all its endeavours.

Both Burhan and Hamdok were in attendance, an AFP correspondent said, while South Sudanese President Salva Kiir oversaw the ceremony.

Sudan's rebels are largely drawn from non-Arab minority groups that long railed against Arab domination of the government in Khartoum.

About 300,000 people have been killed in Darfur since rebels took up arms there in 2003, according to the United Nations.

Conflict in South Kordofan and Blue Nile erupted in 2011, in the wake of South Sudan's independence, resuming two decades of war.

The agreement covers key issues around security, land ownership, transitional justice, power sharing, and the return of people who fled their homes because of fighting.

It also provides for the dismantling of rebel forces and the integration of their fighters into the national army.

Rebel members of the Sudan Liberation Movement (SLM) and the Sudan People's Liberation Movement-North (SPLM-N) had provisionally initialled the agreement with the government late on Saturday.

However, an SLM faction led by Abdelwahid Nour and a wing of the SPLM-N headed by Abdelaziz al-Hilu refused to take part.