The women walked miles through the dusty streets of Maiduguri, in the northeastern corner of Nigeria, carrying their emaciated children. At 7 a.m., they began lining up to wait, for hours, to be handed a small, red packet containing a special paste that could bring their children back from the brink of starvation.

The children were eerily listless; they did not run, shout or even swat the flies off their faces. Their tiny, frail frames made many appear years younger than they were. Near the head of the line, Kaltum Mohammad clutched her two-year-old daughter, Fatima, who weighed just 16 pounds.

Women and children like these waited for treatments in the half-dozen camps and clinics visited by The New York Times last November. Now, six months into the United States’ withdrawal of foreign aid, many of the sites are closed, some permanently. At others that remain open, rooms once filled with boxes of the lifesaving packets are close to empty.

Starvation in Gaza has brought intense international attention to the horrors of famine, but less attention has been paid to a wider issue: the dismantling of U.S.A.I.D. has worsened the problem of severe hunger and malnutrition throughout the world.

Saving children with severe acute malnutrition is simple and inexpensive. Each packet costs less than 30 cents, but contains a high-calorie mix of peanuts, sugar, milk powder and oil — flavors appealing to children — and a blend of vitamins and minerals. A complete six-week treatment for a severely malnourished child runs to less than $45.

U.S.A.I.D. funded roughly half the world’s supply of ready-to-use therapeutic food, or R.U.T.F., purchasing some directly from American manufacturers and funding the United Nations Children Fund, or UNICEF, to manage its distribution.

All those grants were abruptly halted when the Trump administration froze foreign aid earlier this year. U.S.A.I.D. eventually reimbursed grantees for costs already incurred. The State Department authorized a $93 million new grant to UNICEF last week, but it is less than half what the government had typically spent. In 2024, the agency spent about $200 million on this work, not including aid for countries and direct grants to organizations that implement programs.

Funds for 2025 have yet to be released to manufacturers, the World Food Programme — which distributes a similar product for moderate acute malnutrition — those who transport the products or the many organizations, like the International Rescue Committee, or Helen Keller International, that run the malnutrition programs.

In response to questions from the Times, the State Department emailed a statement asserting that lifesaving malnutrition programs “remain a priority.”

“Malnutrition treatment is among the first new obligations of foreign assistance funding,” the statement said.

But it also said that “other actors — including national governments and international humanitarian organizations — must step up.”

President Trump has made the same argument for many aid programs, saying the United States should not have to carry the bulk of the burden of caring for the world. Though other countries do already contribute, and some organizations are scrambling to fill the gap, it is unlikely that they can do so quickly enough to help the children who are now in need.

Increasingly, some governments such as Nigeria, Kenya and Burkina Faso have been contributing by hosting factories that manufacture the packets. The Child Nutrition Fund, started by UNICEF, the British government and others, encourages governments to finance supply by offering a 1:1 match for every dollar.

Before the sudden withdrawal of aid, “things were absolutely moving in the right direction,” said James Sussman, a spokesman for the International Rescue Committee.

Now, boxes containing millions of dollars worth of the lifesaving packets are stuck at every link in the supply chain: in manufacturers’ warehouses, at shipping companies, in cities that received the shipments and in treatment centers that have shut down all over the world.

In nearly a dozen countries, the supply chain for the packets has become so unstable that thousands of children are at high risk of dying, according to organizations that help distribute the treatments. Tens of thousands more could be in danger in the coming weeks and months if funds for this year do not move quickly.

“We have seen the mortality rates in the hospitals increasing by the day,” said Aliyu Mohammed Jabo, Helen Keller International’s director for Nigeria. “This is the ugly situation that we are facing because of this funding cut.”

In Nigeria, 150 clinics operated by the World Food Programme in Borno and Yobe states, which provided treatment for more than 300,000 children below the age of 2, shut down at the end of July. In Bauchi state, Helen Keller International has had to stop treating malnutrition in 16 of its 17 centers, leaving more than 17,000 children without treatment.

In eastern Chad, Mali and Niger, malnutrition treatments are unavailable or in dangerously short supply. Clinics in northeast Syria, Burkina Faso and Kenya have closed down. In South Sudan, the International Rescue Committee estimates that it will have to close 62 static treatment sites and nine mobile clinics if funding is not restored by September.

In Afghanistan, I.R.C. warehouses are bare, despite 900,000 children who are in desperate need of treatment for severe acute malnutrition. Nepal has no supply in about half of its provinces, and is facing a nationwide shortage starting this month, endangering about 200,000 malnourished children, including about 25,000 who are at risk of death.

Several other countries, including the Democratic Republic of Congo, Ethiopia and Madagascar, similarly have only enough products to treat children for a few more weeks or months.

Maryam Mohamed, 35, is mother to three boys under 4, all severely malnourished. She also has three older boys who are not much better off, but it’s the young ones who most need help. In the past few months she has taken them to a series of different centers in Maiduguri as one after another has shut down, sometimes walking 45 minutes or more each way, with one boy on her back and two in her arms.

She now brings them to Mashamari camp in Maiduguri, where the supply of treatments is expected to run out this month.

“I wish they will have a change of decision,” she said about the Trump administration, through a translator. “They should please try to help by not stopping the supply.”

Last week, after months of delays, the State Department authorized $93 million for UNICEF, its first large grant for 2025, to supply R.U.T.F. to 12 African countries and Haiti. Part of the grant is for distributing 11,000 metric tons of packets, enough for about 800,000 children, to last through June 2026. Some money will also be spent to transport and distribute more than 1,200 metric tons of stalled packets — enough for about 87,000 children.

But UNICEF expects that it will be two to three months before the products are delivered, according to Helen Wylie, a spokeswoman for the organization.

After orders are placed and products manufactured, it can take months for treatments to reach people.

Secretary of State Marco Rubio has repeatedly said that no children have died as a result of the cuts to foreign aid and the dismantling of U.S.A.I.D., calling reports of any deaths “false” and “fake.”

But several organizations, including Doctors Without Borders and the aid group Action Against Hunger, have reported deaths in children related to malnutrition. More timely and precise estimates of deaths are difficult, because many of the programs that track children in need have shut down, and most organizations dare not speak up against the administration, fearing retaliation.

“No one’s counting these children,” said Jeanette Bailey, director of Nutrition for the International Rescue Committee, among the largest of groups implementing the treatments.

“With pretty strong certainty, we know children are dying,” she added. But, “we don’t know how many.”

One global study has estimated that more than 160,000 children might die each year if the funds are not restored.

Acute malnutrition, also called wasting, is thought to affect about 43 million children worldwide. Even when aid flowed freely, it did not reach many of them. In 2023, R.U.T.F. was dispensed to 9.3 million children, according to UNICEF.

The first 1,000 days of life in particular are critical for brain development. Severely malnourished children have impaired immune responses, may suffer permanent cognitive damage, and are more vulnerable to infections, even after treatment. They are up to 11 times as likely to die as a healthy child is. Severe wasting accounts for as many as one in five deaths of children under 5 worldwide.

By the time a child reaches a treatment center, he or she may have only hours to days to survive. “It really comes down to the children who do not have time to waste,” said Navyn Salem, who runs Edesia Nutrition, one of two large American manufacturers.

In previous years, American farmers supplied the raw ingredients — peanuts, milk powder and soy — to Edesia and Mana, another large American manufacturer. The finished product was transported by truck to major American ports, then shipped to the ports of Africa, where it would be unloaded and stored. An intricate network of organizations then transported and distributed the boxes.

The stop-start-stop of work orders and the dissolution of U.S.A.I.D. has thrown the system into disarray. U.S.A.I.D.’s activities have in theory been transferred to the State Department, but the department has neither the personnel it needs to restart all activities — even less so after widespread layoffs earlier this month — nor the systems needed to release funds.

The department “continues to strengthen internal systems and personnel capacity to ensure timely, accountable delivery of lifesaving humanitarian programs,” a spokesperson for the State Department said in an email.

In the meantime, some organizations are burning through their reserves, but many small ones have folded.

Others are looking to philanthropy. Mana received a gift of $20 million from a British philanthropist, and donated about 500,000 boxes to UNICEF. Edesia has raised $2 million in private funding and is shipping some boxes to the neediest sites on its own.

Without more funds, the companies will have no money left to buy raw materials, and are in danger of defaulting on contracts from farmers in 25 states.

“The American farmers that we work with can only hold on for so long as well,” Ms. Salem said. “So it’s been a waiting game, a very stressful waiting game.”

Edesia recently shipped 122,000 boxes to Sudan, and still has more than 185,000 at its warehouses. UNICEF will use the new funds to ship those products soon, according to the State Department. Mana, too, has already been paid for 400,000 boxes which have yet to ship; 100,000 are slated to move to South Sudan some time in the coming weeks.

Even if funding were to resume tomorrow, it takes weeks to ship products to their destinations. For R.U.T.F. to reach locations in South Sudan, for example, the products must first be shipped to Mombasa, Kenya — or produced locally in Kenya — then transported by road through Kenya and Uganda to Juba, the capital, and then to more remote parts of the country.

The roads are rough, especially in the rainy season, and boxes may take two or three months to reach the sites, said Stephane Doyon, an operations manager for Doctors without Borders. In Afghanistan, the time to delivery may stretch to eight or nine months, he said.

That may be too late for some children.

Chi Lael, a spokeswoman for W.F.P. in Nigeria., sat in a car just outside the Nana Kashim clinic in Maiduguri, a few days before it shut down at the end of July. W.F.P. would typically be scaling up in order to reach more people in July, the lean season, when food stocks dwindle and prices rise.

“A halt in assistance at a time where people are the hungriest, when they have less access to food, when prices of food are much higher,” she said, her voice breaking. “It’s the worst time imaginable to stop providing assistance.”

Ismail Alfa contributed reporting.