Seoul expressed deep concern Wednesday over North Korea’s words and actions, calling them “senseless” and warning again that Pyongyang will have to bear the final consequences.

“We clearly warn that North Korea’s senseless words and actions will not be tolerated anymore,” said Yoon Do-han, President Moon Jae-in’s senior public relations secretary.

He was referring to the remarks from Kim Yo-jong -- sister of North Korean leader Kim Jong-un -- criticizing Moon’s speech on Monday, the 20th anniversary of the June 15 inter-Korean declaration.

He said Yo-jong’s words showed that the North did not fully comprehend Moon’s words, and that they fundamentally damage the trust built between Moon and the North Korean leader.

Yoon also criticized North Korea for revealing that Seoul had suggested sending special envoys, saying the North had deliberately misinterpreted Seoul’s intentions and that revealing such information without consent was unprecedented.

“The recent statements and actions by the North are not only of no use, but the North will have to take sole responsibility for all the developments that follow.”

Yo-jong’s response to Moon’s speech was revealed by the Korean Central News Agency on Wednesday. In the statement, she said the speech was little more than the excuses of a “scoundrel.”

In the statement, Yo-jong also called Moon’s speech an “expression of cowardice and subservience,” saying Moon’s actions on inter-Korean relations showed the South’s subservience to the US.

The statement concluded with yet another threat against the South.

“The only thing the South’s officials will be able to do is regret and lament,” Yo-jong said in the statement.

“In time, the South’s officials will feel to the bone the high price of betraying faith.”

Her vehement attack on Moon came a day after the North publicly demolished the inter-Korean liaison office in the North Korean city of Kaesong, and again warned of the resumption of military hostilities.

The North’s military also continued its threats against Seoul on Wednesday, adding details to the warnings that Pyongyang had issued in recent days.

In a statement released through the KCNA, the General Staff Department of the North’s Korean People’s Army said military units will be deployed to the Kaesong industrial park and the Kumgangsan resort.

The statement also revealed plans to reconstruct outposts within the demilitarized zone and resume drills in border areas including the West Sea. If carried out, the moves would be in direct violation of the inter-Korean military agreement signed in September 2018.

The North’s military went on to say that locations suitable for sending propaganda materials across the border will be opened to the general public, and other plans will be submitted to the Workers’ Party of Korea.

The statement was met by a stern warning from the South’s military, which echoed the presidential office in stressing consequences for Pyongyang.

“The measures will nullify the two Koreas’ efforts to improve relations and to maintain peace on the peninsula over the past 20 years. If they are put into action, the North will pay the price,” said Jeon Dong-jin, director of operations at the Joint Chiefs of Staff.

South Korean Minister of Unification Kim Yeon-chul, meanwhile, offered his resignation, taking responsibility for the state of inter-Korean relations.

“I have decided to step down, taking all responsibility for the deterioration of inter-Korean relations,” Kim told reporters Wednesday. He then apologized to the public for failing to meet its expectations for peace on the peninsula.

He also said he felt that it was part of his duty to provide an opportunity to turn the situation around -- hinting, possibly, that he hopes his resignation might prompt inter-Korean dialogue.

“I think that there was a point in time when the current deterioration of relations could have been predicted. I think that somebody must take responsibility.”

By Choi He-suk (cheesuk@heraldcorp.com)