Officials worry the disaster could spark war with Seoul - and involve US troops.
North Korea, the world's most cloistered society, is confounding both friend and foe alike about the depth of the food shortage it now confronts.
That there is serious hunger is not in doubt. The issue is whether a humanitarian disaster is looming that could compel a desperate North Korea to start a war that would embroil the 37,000 American troops in South Korea.
Using its vast intelligence-gathering armory, the US is trying to fathom the depths of the shortage. And China may also be boosting its efforts to do the same.
But on the US side, officials say conflicting analyses from different agencies and a paucity of ground-level data from inside the world's last Stalinist bastion have left them without a reliable picture of the crisis.
"The question of the food problem in North Korea is the most hotly discussed and debated issue right now," says Kurt Campbell, a deputy assistant defense secretary who oversees US security policy in East Asia. "Personally, I am not very satisfied with the sort of assessments that I get, because they tend to vary not in terms of one magnitude, but two magnitudes."
US officials hope some answers might be provided by Hwang Jang-yop, architect of North Korea's juche ideology of self-reliance and former tutor of top leader Kim Jong Il. He defected to South Korea earlier this year. But they have yet to talk to him and are unsure of how much he knows.
The conflicting analyses and the dearth of information are fueling concern among some Clinton administration officials about Pyongyang's intentions. Adding to their concerns are disturbing new UN assessments of the food shortages, as well as the breakdown in April of a US-South Korean effort to persuade the North into negotiating a permanent peace to replace the truce that stilled the 1950-53 Korean War.