JAKARTA, Indonesia — An explosive eruption of Mount Dukono on a remote Indonesian island killed three hikers, authorities said Friday. About 20 climbers set out Thursday to ascend the nearly 1,355-meter (4,445-foot) volcano on the island of Halmahera, in defiance of safety restrictions, said North Halmahera police chief Erlichson Pasaribu. They became stranded when Dukono erupted at 7:41 a.m. local time, spewing a thick ash column that rose about 10 kilometers (6.2 miles) above the summit. The