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 refugee camp in Maiduguri, Muna Garage, 20 children under the age of 5 died in a single week last month, she said.

Maiduguri is estimated to host between 1.2 million and 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, then abruptly disbanded the state 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.

The 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," he told a news conference, accusing government officials, camp officials and the military guarding the camps. "We have been living as prisoners, and the food meant for our care is being sold in the open market."

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

The crisis in Maiduguri, where markets are filled with fresh vegetables and fruit, is in addition to what the UN 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.