North Korean farmers in Gaepung County, North Hwanghae Province are seen from the unification observatory in Paju, South Korea, near the border with North Korea, Aug. 10. Yonhap

North Korea on Wednesday slammed South Korea and the United States again for going ahead with joint military exercises, warning it will make the allies feel a serious security crisis every minute.

Kim Yong-chol, head of the North's United Front Department handling inter-Korean affairs, made the remarks in a statement carried by the official Korean Central News Agency, saying the South Korean authorities have defied the opportunity to make a turn in relations.

The denouncement comes just a day after the sister of North Korean leader Kim Jong-un criticized Seoul and Washington as they kicked off a preliminary training Tuesday ahead of next week's main exercise.

"We will make them realize by the minute what a dangerous choice they made and what a serious security crisis they will face because of their wrong choice," he said.