DAKAR, Senegal - Aid groups warned Monday they are nearly $200 million short of the money needed to fight a growing hunger crisis that threatens more than 1 million children across western and central Africa this year.

Aid agencies first warned of a pending emergency in late 2011, and now say women in Chad are searching anthills for grains in order to survive. Others are travelling by donkey in hopes of getting their malnourished children to feed centres.

Action Against Hunger, Oxfam, Save the Children and World Vision said they collectively need nearly $250 million to help people in the eight countries that have been hard hit by drought, high food prices and fallout from the global economic meltdown.

The groups said they have only been able to raise $52 million so far, and they don't want donors to wait for shocking images of starving children to contribute money, said Paula Brennan, who is leading Oxfam's response to the food crisis in the Sahel.

The call for funds comes less than a year after famine hit the Horn of Africa on the other side of the continent, and after several previous food emergencies in the Sahel since 2005.

"What we're saying this time is don't wait until that point; don't wait until people are dying," Brennan said.

More than 15 million people are at risk in this zone that includes some of the poorest countries in the world: Chad, Mali, Niger, Mauritania and Burkina Faso, as well as parts of northern Senegal, northern Nigeria and Cameroon.

"Some families are resorting to eating wild leaves, others are barely able to feed children one meal a day," said Chris Palusky, response manager for World Vision.

This year's food crisis is being further complicated by the political instability in northern Mali, where separatist rebels and Islamist groups have made the area too insecure for most aid agencies to operate. More than 260,000 Malians have fled their homes, with some 129,000 seeking refuge in Mauritania, Niger, and Burkina Faso -- countries that are also grappling with drought and hunger.

Families are also receiving fewer remittances from relatives working abroad because of the global economic downturn. And others who used to work in Libya and send money back home have instead returned, meaning less money for families and another mouth to feed.

The U.N. children's agency also has raised only about 38 per cent of the funds it needs to address hunger in the Sahel, said UNICEF spokesman Martin Dawes.

"The money and resources that come in earlier means they will be more efficiently used. If people gave us money in August, it would still save lives but it would be vastly more expensive," he said.

"There will be massive tragedy unless things are done," he said. "Now, it's really up to the world."