An American aid worker abducted by gunmen in the war-torn Sudanese region of Darfur on Monday described the "nightmare" of her situation in a telephone call to AFP. "In the past it was okay, but now it is not. They are threatening me, my life, my health," the woman, who works for US aid group Samaritan's Purse, said. She was kidnapped in mid-May in the village of Abu Ajura, south Darfur, along with two Sudanese colleagues who have since been released.