The sister of North Korean leader Kim Jong-un said Tuesday that the United States has "wrong" expectations after US National Security Adviser Jake Sullivan called Kim's comments about dialogue with the US an "interesting signal."

The statement from Kim Yo-jong also came a day after US Special Representative for North Korea Sung Kim said the US has offered to meet with the North "anywhere, anytime without preconditions" and looks forward to Pyongyang responding positively to the overtures.

"I heard the news that the US National Security Advisor had mentioned that he regards the position towards the US as an 'interesting signal,'" she said in the statement carried by the official Korean Central News Agency said.

"A Korean proverb says that 'In a dream, what counts most is to read it, not to have it,'" she said. "It seems that the US may interpret the situation in such a way as to seek a comfort for itself. The expectation, which they chose to harbour the wrong way, would plunge them into a greater disappointment."

During a key meeting of the North's ruling Workers' Party, leader Kim said the country should be prepared for both dialogue and confrontation with the US and urged efforts to stably control the situation on the Korean Peninsula.

In an interview with ABC News on Sunday, US National Security Adviser Jake Sullivan called Kim's comments an "interesting signal" and said the US will "wait to see whether they are followed up with any kind of more direct communication to us about a potential path forward."

On Monday, the US special envoy for the North called for Pyongyang to return to talks.

"We continue to hope that the DPRK will respond positively to our outreach and our offer to meet anywhere, anytime without preconditions," Kim said after talks with his South Korean counterpart, referring to the North's official name, the Democratic People's Republic of Korea.

Experts said that Kim Yo-jong's statement should not be construed as a rejection of US overtures for dialogue but a demand that Washington come up with more incentives for Pyongyang to return to the negotiating table.

"I don't think that the statement represents a rejection of dialogue offers," Yang Moo-jin, a professor at the University of North Korean Studies, said.

"It should rather be seen as demanding more concrete and genuine reasons that could justify its return to dialogue than just making such vague proposals for a meeting without preconditions," he added.

Nuclear talks between the US and the North have remained stalled since the Hanoi summit between then US President Donald Trump and Kim in 2019 ended without a deal.

North Korea has demanded the US drop its hostile policy against Pyongyang as a major precondition for its return to dialogue. Experts believe the North views the joint miliary drills between South Korea and the US as part of such policy. (Yonhap)