Witnesses in Khartoum told AFP they could hear "shooting in the south of the city", on the sixth day of the one-week ceasefire which expires Monday night.

The truce aimed to allow humanitarian aid for civilians, delivered through secure corridors, but there were "violations by both parties that significantly impeded" those goals, according to the mediators.

"Both parties have told facilitators their goal is de-escalation to facilitate humanitarian assistance and essential repairs, yet both parties are posturing for further escalation," they said in a joint statement.

The joint statement said both forces had impeded humanitarian efforts, including through the presence of snipers near hospitals in RSF-controlled territory, and army "elements" stealing medical supplies.

In other violations, the mediators reported a confirmed air strike on Saturday that reportedly killed two people in Khartoum and a separate air raid "that damaged Sudan's currency printing press."

It said the RSF has occupied "civilian homes, private businesses, and public buildings", some of which were looted.

Numerous ceasefires were previously announced and immediately violated, but the United States and Saudi Arabia said this one is different because it is a signed deal supervised by a monitoring committee.

The RSF affirmed their "readiness to engage in further negotiations...to explore the feasibility of extending the ceasefire and humanitarian arrangements," depending on the army's "sincerity and commitment".

For its part, the army said it was "examining the possibility of agreeing to extend the current ceasefire".