North Korea could conduct a nuclear test at "any time" while Washington's response to such a provocation would be taken in "very close" coordination with its two Asian allies, U.S. special envoy for North Korea Sung Kim said Tuesday.

But the U.S. government will remain open to dialogue with North Korea toward the denuclearization of the Korean Peninsula even if Pyongyang moves ahead with its first nuclear test since 2017, he said.

"On timing, I don't have anything more. They have obviously done the preparations in Punggye-ri (test site), and my understanding is they could test any time," Kim said in a telephone briefing.

This photo of the Hwasong-17 new type intercontinental ballistic missile being displayed during a military parade in Pyongyang on April 25, 2022, appeared in North Korea's Rodong Sinmun on April 26. (Photo courtesy of Korea Media)(Kyodo)  

The remarks came as North Korea fired eight ballistic missiles from various parts of the country on Sunday, which according to the official would be the largest number of ballistic missiles ever launched in a single day by the country.

"North Korea has now launched 31 ballistic missiles in 2022, the most ballistic missiles it has ever launched in a single year, surpassing its previous record of 25 in 2019," Kim noted, adding, "And it's only June."

North Korean senior officials have also used "rhetoric that could suggest the use of tactical nuclear weapons," according to Kim.

But the envoy said the United States will seek dialogue with North Korea without preconditions despite the launching of unprecedented numbers of ballistic missiles.

On the question of whether Washington will remain committed to dialogue should a nuclear test happen, the envoy said officials of the administration of President Joe Biden have made clear that "we are deeply committed to finding a diplomatic path forward."