The UN budget committee agreed on $600 million in cuts from current costs and slicing 7.5 percent off the US bill following calls by Trump to slash funding.
A tentative deal on nearly $600 million in cuts to the UN peacekeeping budget has been reached following weeks of tough negotiations over US demands for sharp cost reductions, UN diplomats said Wednesday.
The United Nations will spend $7.3 billion on peacekeeping in the coming year, down from the current budget of $7.87 billion, roughly a seven percent cut, according to diplomats familiar with the negotiations.
The United States, the biggest financial contributor to the peacekeeping budget, had sought a nearly $1 billion cut to the bill and the European Union had also pushed for savings to bring costs down to $7.3 billion.
Negotiators clinched the budget deal at 4:30 am Wednesday after marathon talks.
Hardest hit by the cuts will be the UN missions in Sudan's troubled region of Darfur and in the Democratic Republic of Congo, the two costliest operations with budgets that run over $1 billion.
A Security Council diplomat who spoke on condition of anonymity said however there will be "cuts across the board" in the 13 peacekeeping missions as a result of US pressure to scale back the budget.
Washington pays 28.5 percent of the peacekeeping budget and 22 percent of the UN's core budget of $5.4 billion.
The deal falls short of the request from UN Secretary-General Antonio Guterres, who had asked for $7.97 billion for the annual budget which runs from July 1 to June 30 of next year.
The deal is expected to be approved by the UN General Assembly on Friday.
"US interests at the UN"
While Trump has described US funding for the UN as "peanuts" compared to its "important work," he complains its share of the peacekeeping bill, currently 28.5 percent, is "unfair." In his 2018 budget proposal he requested Congress approve only $1.2 billion for UN peacekeeping.
US Ambassador Nikki Haley told US lawmakers in Washington on Wednesday that Trump's proposed US federal budget was "making a point that he wanted to strengthen the military and it was putting the United Nations on notice."
"I have used that as leverage ... now we're seeing a lot of the other countries come forward and say 'yes we should do reform,'" Haley said. "I really do think the message was effective."
The United States is also reviewing each of the UN peacekeeping missions as annual mandates come up for renewal by the UN Security Council in a bid to cut costs. The United States is a veto-wielding member of the council, along with Britain, France, Russia and China.
Big cuts to Darfur mission
The Security Council is expected to vote as early as Thursday on significant cuts to the 17,000-strong joint African Union-UN mission in Darfur known as UNAMID.
Britain on Wednesday circulated a draft resolution that provides for a two-stage drawdown over the next 12 months, in line with the recommendations of a joint AU-UN report released last month.
The measure would cut UNAMID force levels to reach 8,735 troops and 2,500 police by June 2018, a 44 percent cut in military personnel and nearly 30 percent in police, according to the report.
The drawdown could be halted if the Sudanese government fails to ensure protection in those areas from where the peacekeepers will withdraw.
Under the proposed measure, Guterres will report to the council after six months on whether "conditions on the ground remain conducive to further reductions."
The draft resolution welcomes a "reduction in military confrontations between government forces and rebel groups," but rights groups maintain that the conflict in Darfur is far from over.
Human Rights Watch has criticised the proposed cuts as "misguided," saying civilians in Darfur still need protection.
Darfur has been engulfed in conflict since 2003, when ethnic minority insurgents mounted a rebellion against President Omar al Bashir, complaining that his government was marginalising the region.
The UN has shut down its mission in Ivory Coast and is planning to pull its peacekeepers out of Haiti in the coming months.
The council is expected to vote this week on the UN mission in Mali, but that peace operation is not expected to face drastic cuts.