The U.N. forces had driven the NKA out of the South past the 38th Parallel (the diving line between South and North Korea) and began pursuit into the North with the objective of destroying the remaining NKA forces. The losses the NKA suffered in the South were huge: Losing 150,000 men and another 125,000 taken prisoner. With U.N., and especially American forces, now in the North, the political leaders of Communist China and the Soviet Union became quite concerned; fearing that a successful campaign against the NKA would leave foreign forces on their borders.