Millions of people on the southern fringe of the Sahara desert face severe food shortages unless donors stump up enough cash to help see them through the next three months, the United Nations said on Wednesday. The U.N. World Food Programme (WFP) said it had received only a third of the $11 million it needs to fund emergency operations in Niger and Mali, two of the world's poorest nations where drought and a locust plague have triggered a food crisis, Reuters reported. "If we have a bad harvest we risk having millions of people affected and we will be headed towards catastrophe," Jamie Wickens, WFP's associate director of operations, told a news conference in Senegal's capital Dakar. The next three months are vital, with $7.2 million needed immediately to ensure subsistence farmers and their families in the arid band of savannah make it through to October when harvesting starts again, WFP officials said. Aid workers say about 3.6 million people are in need of food aid in Niger, the worst-hit nation in the Sahel region which runs along the southern edge of the Sahara. --More 2013 Local Time 1713 GMT