The Rapid Support Forces, at war with the army since April 2023, appears to be preparing an assault on the central Kordofan region after it captured El-Fasher, the last army stronghold in Darfur, just over a week ago.

"The Security and Defence Council will hold a meeting today to discuss the US truce proposal," the source said on condition of anonymity because they are not authorised to brief the media.

The so-called Quad group -- comprising the United States, Egypt, the United Arab Emirates and Saudi Arabia -- has been engaged in months of diplomacy aimed at securing a truce in the more than 30-month conflict in Sudan.

In September, the four powers proposed a three-month humanitarian truce, followed by a permanent ceasefire and a nine-month transition to civilian rule, hinting at excluding both the army and the RSF from the transitional process.

The Sudanese army-aligned government immediately rejected the plan at the time.

In the aftermath of the RSF's assault on El-Fasher, reports emerged of mass killings, sexual violence, attacks on aid workers, looting and abductions during the offensive.

The International Criminal Court on Monday voiced "profound alarm and deepest concern" over such reports, warning that such acts "may constitute war crimes and crimes against humanity".

Massad Boulos, the US president's senior advisor for Africa, held talks in Cairo on Sunday with Egyptian Foreign Minister Badr Abdelatty.

During the talks, Abdelatty stressed "the importance of concerted efforts to reach a humanitarian truce and a ceasefire throughout Sudan, paving the way for a comprehensive political process in the country", according to a foreign ministry statement.

On Monday, Boulos met Arab League chief Ahmed Aboul-Gheit and briefed him on recent US efforts in Sudan to "halt the war, expedite aid delivery and initiate a political process", according to an Arab League statement.

Despite repeated international appeals, the warring sides -- both of which are accused of committing atrocities -- have so far ignored calls for a ceasefire.

The UAE is accused by the UN of supplying arms to the RSF -- allegations it has repeatedly denied. Meanwhile, the Sudanese army has received support from Egypt, Saudi Arabia, Turkey and Iran, according to observers.

The fall of El-Fasher gave paramilitaries control over all five state capitals in Darfur, raising fears that Sudan would effectively be partitioned along an east-west axis.

The RSF now dominates Darfur and parts of the south while the army holds the north, east and central regions along the Nile and Red Sea.