Malnutrition among North Korean children has fallen, but more than a third still don't have enough food and the country needs substantial aid to get through 2005, U.N. agencies said Monday.

The number of malnourished or stunted North Korean children under 6 has dropped to 37 percent, compared with 42 percent in 2002, according to a survey by the World Food Program (search) and UNICEF (search). It found that children with acute malnutrition fell from 9 percent to 7 percent.

"Food aid has worked," Richard Ragan, director of the WFP's operations in the North, said at a news conference in Beijing. "Now is not the time to back off from it."

Pierrette Vu Thi, the country's UNICEF representative, warned against complacency.

"Chronic malnutrition and underweight are still high by World Health Organization (search) standards, indicating that efforts need to be sustained," she said.

The study assessed 4,800 children under 6 and 2,109 mothers with children under 2. It covered North Korea's capital, Pyongyang, and seven of its nine provinces.

While the condition of children has improved, the number of mothers who are malnourished was unchanged from 2002. More than 150 surveyed mothers were also anemic.

"We need to step up efforts to break the vicious cycle of malnourishment in mothers (which impact) the chances of a good start to life for their children," Vu Thi said.

The North's isolated Stalinist regime has relied on foreign aid to feed its 24 million people since disclosing in the mid-1990s that production at its state-run farms had collapsed following decades of mismanagement and the loss of Soviet subsidies.

In 2002, economic reforms were introduced and outsiders had hoped they would help alleviate chronic hunger.

But products at fledgling private markets cost too much for most North Koreas, Ragan said.

And while the 2004-05 growing season produced 4.2 million tons of rice, corn and other grain, it still fell short of the 5.1 million tons needed to meet the population's basic needs, Ragan said.

In 2005, agencies still will require 500,000 tons of food for programs to feed 6.5 million people, mostly children, pregnant women and the elderly, he said.

Aid agencies have enough food to last until June, but if foreign support declines, "it's likely that the nutritional achievements that are in this report will relapse," Ragan said.