ABU DHABI — United States President Donald Trump's Africa envoy said on Tuesday that neither of Sudan's warring sides had accepted a new ceasefire proposal, while urging both to agree to the internationally backed plan without preconditions.

Renewed efforts for a truce came after Trump said last week that he would move to help end the war in Sudan, after Saudi Arabia's Crown Prince Mohammed bin Salman urged his intervention in this matter during his visit to Washington.

"We appeal to both sides to accept the humanitarian truce as presented without preconditions," US envoy Massad Boulos told reporters in Abu Dhabi, capital of the United Arab Emirates, during a joint media briefing with UAE presidential adviser Anwar Gargash.

"We would like them to accept the specific text that was presented to them," he said.

The plan was presented by Washington on behalf of the Quad, which in addition to the US includes Saudi Arabia, Egypt and the UAE.

On Monday, Sudan's paramilitary Rapid Support Forces announced a unilateral three-month ceasefire.

RSF commander Mohamed Hamdan Dagalo said his fighters would halt operations to allow aid deliveries and protect civilians. The group agreed to the truce to offer "hope" to a population "exhausted by this war", he said in a televised address.

Dagalo pledged to set up a field mechanism monitored by the Quad, the African Union and other international bodies to ensure aid reaches civilians. He vowed to hold RSF members accountable for abuses and safeguard the offices of humanitarian organizations.

Meanwhile, Sudan's army chief Abdel Fattah al-Burhan slammed the latest Quad proposal as the "worst yet" and "biased", citing Abu Dhabi's participation.

US envoy Boulos denied Burhan's accusations.

"We have to overlook those comments and remarks and focus on the heart of the matter which is the humanitarian crisis," Boulos said.

In recent weeks, reports of atrocities in Sudan have shocked the world after the RSF seized El Fasher at the end of October, the last major city that remained outside of their control in the vast western region of Darfur.

On Nov 6, the RSF announced they had agreed to a proposal for a humanitarian truce put forward by the Quad mediators.

The Sudanese government had rejected an earlier plan in September, which excludes both the military and the RSF from Sudan's postwar political process.

That proposal included a three-month humanitarian truce, followed by a permanent ceasefire and a nine-month transition to civilian rule.

AGENCIES - XINHUA