Food aid is due to stop in January in a country taking in hundreds of thousands of refugees from Sudan’s war.

Financial constraints and soaring humanitarian needs have already forced the WFP to suspend assistance to internally displaced people and refugees from Nigeria, Central African Republic and Cameroon from December, it said.

From January, those cuts will extend to people in crisis in Chad, the WFP said on Tuesday in a statement.

More than 540,000 refugees have crossed from Sudan into Chad since war erupted seven months ago between the Sudanese army and the paramilitary Rapid Support Forces (RSF), according to the International Organization for Migration.

Many have fled from West Darfur, where ethnically driven violence and mass killings erupted again this month in the state capital, el-Geneina, pushing thousands more people to flee.

“It is staggering, but more Darfuris have fled to Chad in the last six months than in the preceding 20 years,” said Pierre Honnorat, WFP’s Chad country director. “We cannot let the world stand and allow our life-saving operations grind to a halt in Chad.”

The WFP said it requires $185m to support people in Chad for the next six months. For months, UN officials have said there is not enough international interest in the crisis and they are underfunded.

“Darfur is rapidly spiraling into a humanitarian calamity. The world cannot allow this to happen. Not again,” UN aid chief Martin Griffiths said in June.