The groundbreaking announcement from Beijing follows international outrage over the death of American student Otto Warmbier and a string of high-level meetings between top diplomats and defence chiefs.
Amid rising tensions between Washington and Pyongyang, top brass at the US Defense Intelligence Agency warned last month that Mr Jong-un’s scientists are on an “inevitable path” to developing an intercontinental nuclear-armed rocket.
Global hostility towards the isolated state intensified sharply last week with the death of 22-year-old Mr Warmbier just six days after he was flown home to Cincinnati, Ohio, after 18 months in jail in North Korea.
The University of Virginia student was held in January last year while touring North Korea and was sentenced to 15 years hard labour after being convicted of stealing a propaganda poster from his hotel room.
Authorities claimed he slipped into a coma as a result of suffering a severe neurological injury from an unknown cause two months into his sentence.
Mr Jong-un’s officials have denied he was tortured and on Friday, the day after his funeral, claimed North Korea was the “biggest victim” of the tragedy and was “insulted” by an international smear campaign.
Despite the mystery over the cause of his death, Mr Warmbier’s parents Fred and Cindy refused to allow a post mortem examination but condemned their son’s “awful, torturous mistreatment” which they said ensured there was “no other outcome possible”.
Anger has grown in the US over his death.
He was one of 16 US citizens held by North Korea since 1996, including three still there.
Young Pioneer Tours, which organised his trip, said it would stop taking Americans to the country after his death.
The talks between China and the US resulted in what Chinese state media called a consensus document.
It declared: “Both sides reaffirm that they will strive for the complete, verifiable and irreversible denuclearisation of the Korean peninsula.”
The Xinhua news agency said the agreement followed talks between diplomat Yang Jiechi and General Fang Fenghui and US Secretary of State Rex Tillerson and Defence Secretary Jim “Mad Dog” Mattis.
Mr Yang later had a private White House meeting with President Donald Trump, who is due to hold talks with Chinese President Xi Jinping at next month’s G20 Summit in Hamburg.
The leaders first met in April and the Xinhua agency called their new accord “an upgrade in dialogue mechanisms” between China and the US.
It added the consensus document calls for both countries to “fully” abide by UN Security Council resolutions and push for further “dialogue and negotiation”.