Air strikes on Sudan’s Southern Kordofan border state may have killed as many as 64 people and caused tens of thousands to flee, the UN said on Wednesday. The northern military has been fighting southern-aligned armed groups in Southern Kordofan — a northern, oil-producing state on the ill-defined north-south border — since June 5, raising tensions as the south prepares to secede on July 9. Humanitarian organisations fear a mounting death toll in the state, which is home to many fighters who sided with the south against Khartoum during the last civil war. “There is a growing sense of panic among some of the displaced populations who find themselves trapped by the ongoing violence and the ethnic fault lines,” the U.N. Office for the Coordination of Humanitarian Affairs (OCHA) said in a report.