SEOUL, Rabi'II 3, 1437, Jan 13, 2016, SPA -- South Korea warned North Korea on Wednesday that the United States and its allies were working on sanctions to inflict "bone-numbing pain" after its latest nuclear test, and called on China to do its part to rein in its isolated neighbour, Reuters reported. With tension high on the border after the North's fourth nuclear test on Wednesday last week, South Korean forces fired shots towards what Yonhap News Agency said was a suspected North Korean drone. It returned to the North after the shots, South Korean military officials told Reuters. --SPA 15:34 LOCAL TIME 12:34 GMT www.spa.gov.sa/w