A severe shortage of jet fuel has forced the United Nations World Food Programme to halve its deliveries of food aid to southern Sudan at the height of the annual hunger season, said a statement carried by dpa Tuesday. Insufficient contributions and the late arrival of donor funds had prevented WFP from pre-positioning food before the rainy season earlier this year. Slow deliveries of fuel, a shortage of tankers, limited storage and a high demand was exacerbated by the closure of Khartoum's only refinery for maintenance causing a "tragic situation for hundreds of thousands of people", the statement added. "This could not have happened at a worse time for the people of Sudan," said WFP Country Director Ramiro Lopes da Silva. As a result, the food aid agency delivered roughly half of its planned 20,700 metric tons for 1.3 million southern Sudanese people last month. The deliveries were made mainly by air from Lokichoggio in northwestern Kenya and by road via Uganda. --More 2320 Local Time 2020 GMT