South Korean presidential administration is not going to tolerate Pyongyang’s insults at Moon Jae-in as well as steps aimed at escalating tensions on the Korean Peninsula, Yoon Do-han, a senior communications secretary of Moon, told a briefing on Wednesday.

"We solemnly warn that we will not tolerate the North's nonsense words anymore," TASS reported quoting Yoon.

According to Yoon, these words dealt a heavy blow to trustworthy relations between the two leaders.

He slammed as senseless and rude a statement by the younger sister of Kim Jong-un, Kim Yo-jong - who is the First Vice Director of the United Front Department of the Workers' Party of Korea. She has earlier criticized the speech of the South Korean president at a ceremony marking the 20th anniversary of the first summit of two Koreas' leaders and the signing of a declaration, calling it "shameless sophism."

Yong Do Khan also criticized Pyongyang for circulating confidential information that Seoul this week wanted to send special envoys to North Korea to defuse the current tense situation. The official dismissed this step as "unprecedented violation of basic etiquette," accusing the North of distorting information about the goals of the anticipated trip.