BEIJING (CNN) -- Two million North Koreans -- nearly 10 percent of the population -- may have died during three years of famine in North Korea, U.S. congressional aides said Wednesday.

Video footage brought back from the secretive communist country by a congressional staff delegation showed sickly, emaciated children, some with stick-thin bodies.

One young child, too weak to sit up, had to be propped up in the corner in an orphanage. Older children filmed during the delegation's week-long visit appeared severely stunted by malnutrition.

To survive the persisting food shortages, North Koreans are eating weeds, grasses and corn stalks that are mashed into powder and sometimes mixed with flour to make noodles or cakes.

"The food shortage continues," said Mark Kirk, one of the bipartisan delegation's four members. "They are out of food. That's clear."

Over the past three years, the famine has killed an estimated 300,000 to 800,000 people annually, with the number of deaths peaking in 1997, Kirk said. He said the figures came from U.S. government sources, refugees and North Korean exiles.

"Two million would be the highest possible estimate," Kirk said.

Deaths were most likely from famine-related illnesses, like pneumonia, tuberculosis, and diarrhea, rather than starvation itself, he said.

Poor medical facilities

To compound the problem, medical facilities are inadequate, where they exist at all, Kirk said.

"We found that the hospitals are really hospices," he said. "There is little or nothing in North Korea's entire health care system. The hospitals have no food, no X-ray film, no aspirin."

Meanwhile, an official from Doctors Without Borders said on Wednesday that the medical aid group may leave North Korea unless the government grants it better access to people sickened by famine.

Doctors Without Borders has distributed medicines in North Korea for a year, but has found it hard to gauge the results because of the government's lack of cooperation, said William Claus, an agency official based in Brussels.

The group, one of a half-dozen aid organizations in North Korea, has 12 people working in three provinces, Claus said.

Farm system ravaged

North Korea's food shortages were precipitated by two years of flooding followed by a drought last year that pushed the reclusive Communist nation's inefficient collective farming system to the brink of collapse.

The famine has left North Korea's 23 million people largely dependent on international aid.

International food aid is clearly saving lives, and the international community is feeding nearly every child under the age of 7, the U.S. delegation said.

The United States -- which fought North Korea in the 1950-53 Korean War and remains a staunch supporter of capitalist South Korea -- is now North Korea's largest donor, contributing 220 million tons of food aid.

More aid sought

In an apparent bid for more U.S. aid, North Korean officials told the delegation they would stop exporting missiles if compensated for lost earnings. House International Relations Committee staff member Peter Brookes said they mentioned a figure of $500 million a year.

Kirk said the offer came from Deputy Foreign Minister Kim Gye Gwan, who also heads North Korea's delegation in four-way talks with China, the United States and South Korea.

This year's crops look better than last year's, but North Korea will still lack food after the harvest, the delegation said.

The government of North Korean leader Kim Jong Il has not implemented any significant reforms to reverse the country's economic decline, it added.

Meanwhile, preparations for Kim's expected presidential inauguration on September 9 were almost nonstop, Brookes said, adding that children were still practicing for the inauguration ceremonies at 11 p.m. one night.

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