JUBA, South Sudan (AP) — Aid groups have warned that South Sudan is running out of medicine and facing its largest hunger crisis.

Doctors Without Borders International President Dr. Joanne Liu said Thursday the country is suffering from a "nationwide lack of essential medicine."

Liu said the drug shortage puts thousands of lives in jeopardy and will disproportionately affect women and children.

World Food Program and the Food and Agriculture Organization warned Tuesday of "alarming" levels of hunger. South Sudan's civil war broke out in December 2013 between forces of President Salva Kiir and rebel leader Riek Machar. The two men signed peace and are slated to form a unity government this month. Aid groups say relief funds are shrinking as the country emerges from the war.