A senior U.N. official says the United Nations is having trouble raising money to address what it says are severe food shortages in North Korea.

In an interview aired Thursday on Japan's NHK television, U.N. Emergency Relief Coordinator Valerie Amos said the world body has so far received less than 20 percent of the $210 million it believes is needed to ensure North Koreans have enough to eat.

Amos, who is visiting Tokyo, said countries have been reluctant to donate because of North Korea's nuclear weapons program and an attack last year on South Korea's Yeonpyeong Island. But she appealed for world governments to contribute, saying there are North Korean women and children in desperate need.

U.N. officials have estimated previously that more than one-quarter of North Korea's population is in urgent need of food assistance. But some South Korean officials say the North is exaggerating the problem so it can stockpile food for a major celebration next year.

Both the United States and the European Union have sent delegations to North Korea to independently evaluate the need for food aid.