Sudan's paramilitary Rapid Support Forces have signed a charter paving the way for a parallel government with its allies, including a former foe who analysts say could offer crucial territory, fighters and border access.

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.

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