North Korea on Wednesday slammed South Korea and the United States again for going ahead with its joint military exercise, 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.

"They must be made to clearly understand how dearly they have to pay for answering our good faith with hostile acts after letting the opportunity go for improved inter-Korean relations," he added.

Kim denounced South Korea for answering the North's "good faith" with "hostile acts," calling Seoul's "much-touted" push for inter-Korean peace "just wordplay." He also said that the North has no choice but to "keep going on what we should," though he did not elaborate on what it will be.

On Tuesday, Kim Yo-jong, the sister of leader Kim, issued a strong-worded statement, slamming South Korea and the US for going ahead with their joint military drill despite her earlier warning that the maneuvers will cloud inter-Korean relations.

She said that the country will further strengthen the country's "deterrent of absolute capacity" to cope with military threats.

US State Department spokesperson Ned Price said earlier that Washington harbors no hostile intent toward North Korea and insisted that the joint military drills are purely defensive in nature.

In response to Wednesday's statement, the unification ministry in Seoul said that it appears to be a repeat of what Kim Yo-jong said a day earlier, adding that the ministry will closely monitor the North's future actions.

Later in the day, the ministry released the government's stance on the North's statement, saying that "the escalation of military tension on the Korean Peninsula is beneficial to no one."

The government also redoubled calls for the North to return to dialogue at an early date for peace and stability on the peninsula and for development of cross-border relations.

North Korea did not answer South Korea's calls through military and liaison hotlines Wednesday morning for the second consecutive day in apparent protest against the military exercise.

The inter-Korean communication lines were restored late last month over a year after the North unilaterally severed them in anger over South Korean activists sending anti-Pyongyang leaflets across the border in June 2020. (Yonhap)