The assurance came as the United States announced $200 million in new aid for Sudan, one of the world's worst humanitarian disasters where tens of thousands have died in fighting since April 2023.

Two US lawmakers said the United Arab Emirates promised to address their concerns and that, as a result, they would drop their attempt to block $1.2 billion in sales of advanced rockets and long-range missiles to the Gulf power.

Senator Chris Van Hollen, a member of President Joe Biden's Democratic Party, released a letter addressed to him from the White House that described UAE assurances on its relationship with Sudan's Rapid Support Forces.

"Despite reports we have received suggesting the contrary has occurred to date, the UAE has informed the administration that it is not now transferring any weapons to the RSF and will not do so going forward," said the letter signed by Brett McGurk, the White House coordinator on Middle East policy.

The UAE has long denied arming the RSF, with which it had a relationship fighting Yemen's Huthi rebels. The UAE embassy did not immediately respond to a request for comment.

In the letter, McGurk promised to offer an assessment on the "credibility and reliability of these assurances" by January 17 -- three days before President Joe Biden hands the White House back to Donald Trump.

Van Hollen applauded the White House intervention and said he would again attempt to block arms sales if the UAE does not comply.

"The United States should use all of our leverage to help bring peace and stability to the people of Sudan," he said on the Senate floor.

Fellow Democrat Sara Jacobs, who led a parallel effort in the House of Representatives, also vowed to "carefully monitor" adherence by the UAE.

"Without the UAE's support, the RSF will not have the same capabilities to wage this war -- making negotiation and a ceasefire a much likelier alternative," she said in a statement.

United Nations experts tasked with monitoring an arms embargo on the Darfur region said last year that accusations the UAE had funneled weapons to the RSF through Chad were "credible."

Trump has shown a greater willingness on selling weapons and in his last term promised advanced F-35 jets and armed drones as part of a deal in which the UAE recognized Israel.

The F-35 purchase languished after Biden defeated Trump in the 2020 election and promised greater oversight of the weapons.

- Eating grass and peanut shells -

The World Food Program warned Thursday that Sudan risks becoming the largest hunger crisis in recent history, with 1.7 million people across the country either facing famine or at risk of famine.

"The world cannot -- must not -- look away from the humanitarian catastrophe that is happening in Sudan on our watch, before our eyes," US Secretary of State Antony Blinken said at a UN Security Council meeting on Sudan.

He announced another $200 million in relief, saying that in some parts of Sudan, people are eating grass and peanut shells to survive.

Edem Wosornu, operations director of the UN Office for the Coordination of Humanitarian Affairs, said $4.2 billion is needed to support Sudan next year.

"The volume of humanitarian aid reaching people in need remains a fraction of what is required," Wosornu told the Council.

Nearly all of the vast Darfur region of western Sudan is now controlled by the RSF, which has also taken over swaths of the neighboring Kordofan region as well as much of the center of the country.

The regular army retains control of the north and east, while the capital Khartoum and its surrounding cities are a battleground between the warring parties.