Donald Trump is proposing to slash American payments to the United Nations by more than 50 per cent, according to US media reports and Western diplomats, who fear drastic cuts to lifesaving aid and peacekeeping missions around the world.
The first details could come on Thursday when the White House will unveil its budget for the year ahead.
Mr Trump is expected to detail billions of dollars in savings to pay for his plan to expand the armed forces without raising taxes.
State Department officials have been told to find cuts of more than 50 per cent in payments to UN programmes, according to a report in Foreign Policy.
Diplomats have been told to brace themselves to expect cuts.
At present the US pays about $10 billion to the UN, made up of its compulsory dues and payments to individuals agencies, funds and programmes, such as peacekeeping, making it the biggest single donor.
It comes at a time when the UN is dealing with a refugee crisis caused by the war in Syria and as it appeals for funds to help 20 milllion people facing starvation in Yemen, Somalia, South Sudan and Nigeria.
Paul Fritz, assistant professor of political science at Hofstra University, said any cuts would be almost catastrophic.
“There’s more pressure on programmes like the World Food Programme and others than there has been in decades,” he said.
At the same time, Mr Trump has managed to end speculation about another financial issue.
His spokesman, Sean Spicer, announced that the president would be donating his salary to a cause selected by White House correspondents.
“I think his view is he made a pledge to the American people he wants to donate it to charity and he'd love your help to determine where it should go,” he said during his regular briefing.
Mr Trump, who is believed to be worth $3billion, promised during the campaign that he would give his $400,000 White House pay cheque to charity without offering any explanation about how it would work – until now.
A number of reporters suggested using the money to fund a journalism scholarship or to protect freedom of the press.