NEW : South Korea says the North needs to show its sincere through action . U.S. admiral says joint military exercises with South Korea wo n't be called off . North says it wants to `` halt hostile military acts , '' reunite families , improve ties with South . " Comment: The US is not going to stop their drills or any other type of war games in the region because they are a defensive measure against an enemy that has been attacking them for years and
NEW : South Korea says the North needs to show its sincere through action . U.S. admiral says joint military exercises with South Korea wo n't be called off . North says it wants to `` halt hostile military acts , '' reunite families , improve ties with South . Letter blasts `` foreign forces , '' says South should have embraced its plans .