The Trump administration has moved to cut $5bn (£3.7bn) in foreign aid that was already allocated by Congress earlier this year.
The president is using an arcane manoeuvre known as a pocket rescission, or a request to claw back approved funds so late in the fiscal year that if Congress does not weigh in, the allocated money lapses.
The move, which aims to cut billions in programmes including the funding of peacekeeping operations abroad, has not been attempted in nearly 50 years.
The budgetary tactic is likely to face legal challenges as it effectively bypasses the legislative branch to directly cut spending.
The decision was announced by the White House Office of Management and Budget in a social media post on Friday.
