MAIDUGURI, Nigeria — Children who escaped Boko Haram’s Islamic insurgency now are dying of starvation in refugee camps in northeastern Nigeria’s largest city as the government investigates the theft of food aid by officials.

Refugees have staged near-daily protests over the past week. In one, women blocked the main highway linking Maiduguri, the Borno state capital, to Kano city for five hours, shouting that their children are starving and they have no drinking water as temperatures soar above 40 degrees (104 Fahrenheit).

Between 10 and 25 percent of children in a 110-bed feeding center are dying, said Doctors without Borders spokeswoman Shaista Aziz. She called that a high percentage even in an emergency. Most of the dying are from refugee camps, she said.

Dozens of babies and children with matchstick limbs and protruding rib cages fill the tents of the feeding center visited by The Associated Press.

Families cannot leave the camps, “so they are completely reliant on food distributions,” said Dr. Natalie Roberts, deputy emergency desk manager for the medical aid group.

Doctors without Borders’ therapeutic feeding program in Maiduguri, where the most malnourished children are treated, “has quadrupled in size in the last weeks, but each time it expands it becomes rapidly full,” Roberts said. In one local camp, Muna Garage, 20 children under the age of 5 died in a single week last month, she said.

At Farm Centre Camp, on Maiduguri’s outskirts, residents said they had received no food in more than one month. They and refugees at other camps said that when they do get meals, it consists only of rice and beans. They get one shovelful a day — literally delivered from a shovel — whether a household has six people or 12, they said.

“We and our children, for about four to five days now, they are not giving us food because when they bring the food items, they (officials) take it to the room and share among themselves instead of giving us what belongs to us,” said one refugee, Binta Lawal.

Maiduguri is estimated to host 1.2 million to 2 million refugees but only a fraction stay in the camps because, as The Daily Trust newspaper reported Tuesday, “Most of the camps have become centers of hunger, malnutrition and communicable diseases.”

Nigeria’s Senate last week announced it was launching an investigation into allegations that food aid is being diverted, and the Economics and Financial Crimes Commission weeks ago said it was doing the same.

The governor of Borno state, Kashim Shettima, last week accused rival politicians of instigating the protests. Shettima has been publicly booed by refugees and residents, with some shouting “Rice thief!” when his convoy passes, several residents told the AP.

Shettima last week abruptly disbanded his government’s committee to feed refugees, which is supposed to provide cooked meals. Shettima’s office said refugees will now get food directly to cook themselves. That poses challenges, as the refugees will need charcoal for fires, cooking oil and clean water.

Angry refugees took to the streets to protest because of several deaths from starvation, said a spokesman for the refugees, Umar Abdulsalam.

“The camp officials have been restricting some of us who are strong from going out. We have been living as prisoners, and the food meant for our care is being sold in the open market,” he told a news conference, accusing government officials, camp officials and the military guarding the camps.

The camps are supposed to be run by the Borno state Emergency Management Agency.

Last week, local reporters and refugees watched as soldiers and local self-defense vigilantes shoved blankets and other aid meant for refugees at Dalori Camp into a tricycle taxi and took off.

Irish rock star Bono and Nigeria’s richest man, multibillionaire Aliko Dangote, visited Dalori on Sunday. A businessman who was there the day before said he watched a truckload of food aid arrive, wait and then leave with all the food. When he questioned a camp official, he was told the food could not be distributed until Bono and Dangote arrived. The businessman spoke on condition of anonymity for fear of losing his government contracts.

The crisis in Maiduguri, where markets are filled with fresh vegetables and fruit, is in addition to what the U.N has called a “catastrophic humanitarian crisis” in northeastern areas of Nigeria recently liberated from Boko Haram, where 2.5 million malnourished people have no access to food and drinking water. Those areas are still dangerous to reach.