"A combination of factors will lead to the worsening of the North's food situation," Kwon was quoted as saying by Yonhap news agency in an interview. He cited shrinking international aid, higher global prices, China's tighter restrictions on fertiliser exports, the intensely cold winter and the spread of foot-and-mouth disease. The cold badly damaged barley and wheat planted last fall for harvesting this summer, the expert said. Kwon and other experts say the foot-and-mouth outbreak will seriously affect farming in the North, which still relies heavily on oxen for ploughing and other agricultural work. The North needs 5.5 million tons of grain a year to feed its 24 million people, Kwon said. Assuming it can import as much grain and receive as much international food aid as it did last year, the shortfall would be about 800,000 tons. Earlier this week, South Korea's Unification Minister Hyun In-Taek also said this year's harvest would amount to "4.1 million tons, plus or minus". Officials from the UN's World Food Programme and Food and Agriculture Organisation have been visiting North Korea since February 10 to assess the food situation after Pyongyang appealed for international aid. They were due to brief diplomats and international agencies in Pyongyang on Friday or Saturday, Yonhap reported. Donations to food aid programmes for North Korea have dwindled due to international irritation at its missile and nuclear programmes. The North has appealed to 40 countries for food aid, a Seoul government official told reporters this week on condition of anonymity. Some Seoul officials question its motives, saying last year's harvest was relatively good. They say it may be trying to stockpile food for celebrations next year of the 100th anniversary of the birth of founding president Kim Il-Sung. In Washington, several US Republican lawmakers at a congressional hearing urged the administration Thursday to deny the North's request for food aid, fearing it would bolster the regime. The Obama administration says it has not yet decided whether to provide aid but would want close monitoring of any assistance.