Dar es Salaam, Feb. 4 -- WASHINGTON: Dozens of senior officials put on leave. Thousands of contractors laid off. A freeze put on billions of dollars in humanitarian assistance to other countries.

Over the last two weeks, President Donald Trumps administration has made significant changes to the U.S. agency charged with delivering humanitarian assistance overseas that has left aid organizations agonizing over whether they can continue with programs such as nutritional assistance for malnourished infants and children.

Then-President John F. Kennedy established the U.S. Agency for International Development, known as USAID, during the Cold War. In the decades since, Republicans and Democrats have fought over the agency and its fun...