Critics say a Trump administration order calls into question the United States’ global standing and reliability.

President Trump’s executive order freezing most U.S. foreign aid for 90 days has thrown into turmoil programs that fight starvation and deadly diseases, run clinical trials and seek to provide shelter for millions of displaced people across the globe.

The U.S. Agency for International Development, or U.S.A.I.D., is the main government organization that provides humanitarian aid, such as food, medical assistance and disaster relief. It has been hit the hardest by the freeze.

Mr. Trump has accused the agency of rampant corruption and fraud, without providing evidence. The billionaire Elon Musk, who has been given the task of cutting federal budgets and programs, boasted online of “feeding U.S.A.I.D. into the wood chipper.”

The Trump administration ordered thousands of the agency’s workers to return to the United States from overseas, put them on indefinite administrative leave and shifted oversight of the agency to the State Department.