About 13 million people living in west and central Africa face a major food crisis unless immediate action is taken, humanitarian group Oxfam warned Thursday.

A dangerous combination of drought, high food prices, reduced harvests, poverty and conflict are driving an emerging crisis across several nations including Chad, Burkina Faso, Mali, Mauritania, Niger and northern Senegal, the group said.

In Chad, the situation already is so bad that some villagers are digging into ant hills to collect grain the insects have stored.

"All signs point to a drought becoming a catastrophe if nothing is done soon," said Mamadou Biteye, Oxfam's regional director for west Africa. "A concerted aid effort is needed to stop tens of thousands dying due to international complacency."

In the countries most affected, malnutrition rates are at between 10-15 percent and more than one million children are at risk of severe acute malnutrition.

The group said that in northern Mali, clashes between the army and Tuareg rebels have forced tens of thousands of people to flee their homes, adding extra pressure for resources in surrounding countries.

Oxfam wants to raise $37 million (28 million euros) to provide food and support to about one million people.