Sudan's paramilitary Rapid Support Forces and allies have signed a charter that paved the way for the establishment of a parallel government, as Sudan's army made advances recently against the rival groups.

Sudan's Rapid Support Forces signed a charter with allied political and armed groups late on Saturday to establish a "government of peace and unity", signatories al-Hadi Idris and Ibrahim al-Mirghani told Reuters.

The RSF has seized most of the western Darfur region and swathes of the Kordofan region in an almost-two-year war, but it is being pushed back from central Sudan by the Sudanese army, which has condemned the formation of a parallel government.

The war in Sudan has killed more than 24,000 people and driven over 14 million people — about 30% of the population — from their homes, according to the United Nations. An estimated 3.2 million Sudanese have escaped to neighboring countries.