People who are experiencing urgent humanitarian crises, and who rely on aid for food, water and healthcare, could feel U.S. cuts immediately, experts warn.

Secretary of State Marco Rubio has approved some waivers for emergency food aid and some salaries after President Donald Trump’s executive order to halt and reevaluate all foreign development assistance prompted an outcry among aid groups around the world.

Many of the frozen programs are aimed at alleviating disease and malnutrition, but even security programs with U.S. funding are shutting down.