President Donald Trump's senior Africa envoy, Massad Boulos, has rejected criticism that the U.S.'s latest proposal to end the Sudan civil war is 'biased'.

The U.S., Saudi Arabia, Egypt, and the United Arab Emirates (UAE) have been attempting to mediate between Sudan's army and the paramilitary Rapid Support Forces (RSF), which have been fighting for more than two years.

On Sunday, Sudan's army chief Abdel Fattah al-Burhan said the latest ceasefire proposal was unacceptable and future ones would also be one-sided as long as the UAE was involved in the negotiations.

The Gulf state denies it is offering support to the RSF, and on Tuesday, Mr. Boulos responded to the bias claims, stating they were unfounded.

He was making reference to something that does not exist, the AFP news agency reports Mr. Boulos as saying at a media briefing.

Burhan had termed the latest peace plan proposal as 'the worst ever' for sidelining the military and permitting RSF's continued existence.

The situation in Sudan remains dire, with over 12 million people displaced amid what the UN has described as the world's worst humanitarian crisis. Despite Burhan's statements accusing U.S. officials of trying to impose conditions, international mediators are still advocating for a resolution to the conflict.