Yonhap also reported yesterday that North Korea has revised its Constitution to make Mr Kim head of state, a promotion that could help normalise his relations with other world leaders ahead of any further meetings with US President Donald Trump.
The South Korean news agency, Yonhap, quotes a source close to White House deliberations on North Korea, as saying that the U.S. is considering sanctions relief for the North Korean nuclear freeze.
Ensuring the continuation of the current political system led by the Kim family is a long-sought goal by North Korea.
The latest statement didn't criticize the US directly.
Despite the warning, it's unclear if North Korean can conduct a major weapons test any time soon because that would likely disrupt a positive atmosphere after the June 30 summit between Trump and Kim at the Korean border village of Panmunjom.More news: Facebook Event Promotes Raid on Area 51 in Amargosa Valley, Nevada
The UN Security Council has passed five rounds of sanctions against North Korea since the country's fifth nuclear test in September 2016.
The two sides have yet to even agree a common definition of denuclearisation, which North Korea has taken to include the US nuclear umbrella protecting Japan and South Korea.
The U.S. government has been carefully analyzing what is behind the shift in North Korea's negotiating strategy. Trump crossed into North Korea and shook hands with Kim becoming the first sitting U.S. president ever to do so.
"The White House, when working-level talks begin, wants to set the conditions whereby they can begin the process of North Korea's denuclearization", the Trump administration source told Yonhap.
Yet despite the new found optimism following the Trump and Kim DMZ meeting, statements from both Washington and Pyongyang indicate that their positions remain unchanged. McCarthy said she can't pinpoint whether Kim likes or dislikes Trump, . but he may be viewing Trump differently from past American presidents.More news: Historic vote on equal marriage and abortion rights for NI welcomed
In an apparent attempt to coax Washington into making concessions, Pyongyang warned in April that it would consider suspending denuclearization negotiations. "The amendment may well be a chance to establish Kim's status as the signer of a peace treaty when it comes, while projecting the image of the country as a normal state", he said.
Kim is believed to have conveyed the intention to Russian President Vladimir Putin and Chinese President Xi Jinping. But last month Russian Federation and China blocked the sanctions committee from declaring that Pyongyang breached the annual import limit.
The two countries were also preparing to declare an end to the Korean War, a 1950-1953 conflict that was halted with an armistice.
"This is not a 'large-scale North Korean defector entry to South Korea, ' as reported in certain outlets", he said.
'It is quite ridiculous for the United States to continue to behave obsessed with sanctions and pressure campaign against the DPRK, considering sanctions as a panacea for all problems, ' North Korea's mission said. "Their first goal in the talks is to prove to the North that they can trust the US and that Washington wants to do something historic to ensure the hostile intent of both sides is now firmly in the past". DPRK is an acronym for the Democratic People's Republic of Korea, North Korea's formal name. No concrete measures were taken in the meantime to guarantee security for North Korea.More news: 'It is something special' - Lampard's work with Chelsea squad hailed by Azpilicueta