Abu Dhabi, UAE - President Donald Trump's Africa envoy on Tuesday said neither warring side in Sudan had accepted the latest ceasefire proposal, urging both to agree to the truce presented by Washington on behalf of mediators without preconditions.

"We appeal to both sides to accept the humanitarian truce as presented without preconditions," Massad Boulos told reporters in the Emirati capital.

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

He spoke at joint media briefing with UAE presidential advisor Anwar Gargash in Abu Dhabi, days after Sudan's army chief Abdel Fattah al-Burhan slammed the latest proposal presented by Boulos, whom he accused of parroting the UAE's talking points.

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Boulos is the father of Michael Boulos, husband to Trump's daughter Tiffany.

Burhan had criticized the latest ceasefire plan presented by the Quad – which in addition to the US includes Saudi Arabia, Egypt, and the United Arab Emirates – saying it was "biased" as long as Abu Dhabi was a member.

The UAE has been widely accused of arming the Sudanese paramilitary Rapid Support Forces, who are at war with the army-backed government. The country denies the allegations.

Some members of US Congress have called for an arms embargo on the UAE until it stops giving material support to the RSF in Sudan.