Nearly a third of children under age 5 show signs of stunting, particularly in rural areas where food is scarce, and chronic diarrhea due to a lack of clean water, sanitation and electricity has become the leading cause of death among children, the agency said. Hospitals are spotless but bare; few have running water or power, and drugs and medicine are in short supply, the agency said in a detailed update on the humanitarian situation in North Korea.
"I've seen babies ... who should have been sitting up who were not sitting up, and can hardly hold a baby bottle," Jerome Sauvage, the U.N.'s Pyongyang-based resident coordinator for North Korea, said in Beijing before presenting the report to donors.
The report paints a bleak picture of deprivation in the countryside, not often seen by outsiders, who are usually not allowed to travel beyond the relatively prosperous Pyongyang, where cherubic children are hand-picked to attend government celebrations and a middle-class with a taste for good food have the means to eat out.
Sauvage's report provides not only further evidence of North Korea's inability to feed its people, but also bolsters critics who say the government should be spending on food security instead of building up its military, testing rockets and pursuing a nuclear program denounced by the U.N., the United States and South Korea.
North Korea says strong military and nuclear deterrents are needed because of what it terms U.S. and South Korean preparations for a northward invasion.
The United Nations called for $198 million in donations for 2012—mostly to help feed the hungry.
The appeal comes at a delicate time for North Korea, which has sought to project an image of stability and unity during the transition to power of the new, young leader, Kim Jong Un.
Yet the government has begun to publicly acknowledge a severe shortage of food for the first time in years.
In late May, in an unusual admission of a food problem by a high-ranking official, North Korea's premier, Choe Yong Rim, urged farmers to do their part in alleviating the food shortage, according to the state-run Korean Central News Agency.
Worries of another drought have also been raised by a reported shortfall of rain this spring in some areas, which will likely lead to reduced harvest in the fall. The apparent effects of the drought were witnessed by The Associated Press in May in South Phyongan province.
"I have been working at the farm for more than 30 years, but I have never experienced this kind of severe drought," An Song Min, a farmer at the Tokhae Cooperative Farm in the Nampho area, told the AP as he stood in parched fields where the dirt crumbled through his fingers.
North Korea does not produce enough food to feed its 24 million people, and relies on limited purchases of food as well as outside donations to make up the shortfall. North Korea also suffered a famine in the mid- and late-1990s, the FAO and World Food Program said in a special report late last year.
About 16 million North Koreans—two-thirds of the country—depend on twice-a-month government rations, the U.N. report said. And there are no signs the government will undertake the long-term structural reforms needed to spur economic growth, it said.
Rations usually consist of barley, maize or rice, if they're lucky, while many children are growing up without eating any protein, Sauvage said. He said malnutrition over a generation can have a severe affect on physical growth, cognitive capacity and the ability to learn.
The land in the mountainous north is largely unsuitable for farming, and deforestation and outmoded agricultural techniques—as well as limited fuel and electricity—mean farms are vulnerable to the natural disasters North Korea is prone to, including flooding, drought and harsh, cold winters, the U.N. report said.
Provinces in the southern "cereal bowl" produce most of the country's grains, but the food does not always reach the rugged far northeastern provinces, the report said. A crop assessment in October 2011 indicated that 3 million people would need outside food help in 2012.
But many donor countries remain skeptical whether food aid would reach the hungry or be diverted to the nation's powerful elite or million-man military.
The World Food Program issued a global appeal for $218 million in emergency food aid in 2011, saying a quarter of North Korea's population needed foreign food handouts to keep from going hungry. It received only $85 million.
South Korea had been one of North Korea's biggest benefactors until conservative President Lee Myung-bak took office in 2008, ending unconditional aid by linking it to progress on North Korea's nuclear disarmament process.
Seoul has no immediate plans to resume massive direct food and fertilizer aid to North Korea, South Korean Unification Ministry spokeswoman Park Soo-jin said Tuesday.
A North Korean long-range rocket launch in April also scuttled a deal with the U.S. that would have sent 240,000 metric tons of food aid in exchange for a moratorium on nuclear and missile tests.
Sauvage noted a welcome focus on agriculture, including crop rotation and organic farming, in this year's joint New Year editorial laying out the government's policies for 2012.
He said that North Korea, proud of its free health care system, runs spotlessly clean hospitals but with limited facilities.
"The health care system is on paper quite sophisticated. The proportion of doctor per household is very high," Sauvage said. "Unfortunately, there's not a lot in the doctor's toolkit."
"You go and visit a hospital in winter and it will not be heated. Never," he said. "There will most likely be no water. There will likely be no medicine other than the medicine that agencies are delivering.
"They have shown us orphanages, kindergartens and hospitals, and I've been able myself to see children who I was told were 9 years old but had physical signs that they were much older than 9, probably 13 or 14 years old, and were evidently undernourished," he said.
Despite the dire conditions, North Korea remains defiant.
The state-run Korean Central News Agency recently accused the West of manipulating food prices as a form of imperialism, and urged North Koreans to become self-sufficient before turning to outside help.
"Dry bread at home is better than roast meat abroad," a KCNA editorial said.
Follow AP's Korea bureau chief at twitter.com/newsjean.
Associated Press writer Hyung-jin Kim contributed to this story from Seoul, South Korea.