Dar es Salaam, Jan. 31 -- WASHNGTON: Trump administration changes have upended the U.S. agency charged with providing humanitarian aid to countries overseas, with dozens of senior officials put on leave, thousands of contractors laid off, and a sweeping freeze imposed on billions of dollars in foreign assistance.

Secretary of State Marco Rubio defended the pause on foreign assistance Thursday, saying “the U.S. government is not a charity.”

Aid organizations say the funding freeze and deep confusion over what U.S.-funded programs must stop work as a result has left them agonizing over whether they could continue operating programs such as those providing round-the-clock nutritional support to extremely malnourished infan...