– President Donald Trump's proposed budget cuts to the United Nations, which runs agencies such as the World Food Program and UNICEF, come at a time when famine is reaching a crisis point in parts of Africa and children in some countries are dying of starvation.

The timing of the proposed cuts has sent chills through the international aid community, which fears that a retreat by the U.S. in relief funding could make a bad situation worse.

Just days before Trump's budget was released, U.N. humanitarian chief Stephen O'Brien warned that the globe is facing its worst humanitarian crisis since the end of World War II.

Two years of drought and failed rains across much of Africa have affected 38 million people in 17 countries.

Without a massive donor injection of $4.4 billion, aid officials estimate, more than 20 million people face starvation and famine in Nigeria's northeast, South Sudan, Somalia and Yemen. The disaster is likely to leave countries fragile for years to come.

The United States, through its humanitarian aid and support for the U.N., has traditionally been at the forefront of global efforts to avert catastrophes such as famine and to relieve the effects of drought on some of the world's poorest people.

The budget process involves negotiations between the White House and Congress that could see changes in Trump's proposal to slash funding for the State Department, as well as the U.S. Agency for International Development and other international programs, by 28 percent, or $10.9 billion, as he seeks to increase military spending by $54 billion next year.

But Scott Paul, senior policy adviser at the humanitarian agency Oxfam, said Trump's budget blueprint sent tremors of alarm through the humanitarian community.

"The message that it sends is that the U.S. is no longer interested in leading or being part of global efforts to mitigate suffering in the world," he said.

Even before Trump's blueprint was unveiled, there wasn't sufficient global support for U.N. and humanitarian efforts to stave off catastrophes in South Sudan, Somalia, northeastern Nigeria and Yemen, Paul added.

"We have these four emergencies on the verge of famine, which from our point of view already signal a failure of will to prevent this historic level of suffering," he said.

For decades, the U.S. has been the largest supporter of the World Food Program as part of a bipartisan congressional commitment to averting famine and starvation. In 2016, the U.S. paid 24 percent of the food program's $8.6 billion budget, or about $2 billion.

But in the future, other countries will have to step up to provide a greater share of disaster assistance, U.S. Secretary of State Rex Tillerson said in Japan on Thursday.

"I think it sends a message that the U.S. is turning inward at a time when we are facing these unprecedented crises that require increasing U.S. engagements and humanitarian assistance," said Bernice Romero, senior director for policy and humanitarian response at Save the Children.

Steve Taravella, senior spokesman for the World Food Program, said the budget blueprint sparked concerns that the U.S. was retreating from its historical support for aid to avert starvation and hunger.

"I think everybody who has seen the numbers that were proposed has some fear that efforts to fend off famine will not get the same support they have in the past," said Taravella. "At the time when we are asking the world for even greater amounts to help stave off famine in these parts of the world, what we are looking at is the possibility of a decrease from our major donor. It's not an abstract threat. Right now, people are dying. They're dying for lack of food."