Neither side has explained why the planned talks between Secretary of State Mike Pompeo and Kim Yong Chol, a key aide of the North Korean leader, were postponed.
Kim Eui-kyeom, the Blue House spokesman, said in a briefing Wednesday, "I don't believe that the postponement [of the high-level talks] means that the North-U.S. negotiations have become null or lost momentum or direction".
The State Department on Monday announced that Pompeo would travel to NY with Stephen Biegun, the US special representative for North Korea, to meet Kim Yong-chol.
"We will reconvene when our respective schedules permit", she said.
"Not only complete denuclearization, but our capacity to verify that that has taken place is also a prerequisite to lifting economic sanctions", he said on CBS.
The June meeting of President Donald Trump and DPRK top leader Kim Jong-un in Singapore was the first summit meeting of an incumbent United States president and a DPRK leader.
At that meeting, Kim, who is seeking relief from tough USA -led sanctions, committed to work toward denuclearization, but his steps since have fallen short of US demands for irreversible moves to abandon a weapons program that potentially threatens the United States.More news: Mueller investigation: what will happen to it under Matt Whitaker?
Kim Yong Chol is a general, a former top intelligence chief and right-hand man to the North Korean leader.
North Korea's Foreign Ministry said the US President Donald Trump's administration had failed to understand its repeated demand.
The meeting comes with the two sides at loggerheads almost five months after the summit, in which Trump and Kim pledged to work toward the denuclearisation of the Korean peninsula. He said he wasn't anxious and that sanctions against North Korea remain in full effect.
Though some experts speculate the threat to build up nuclear forces could have been posturing by Pyongyang to gain leverage for the now-postponed talks, a source with knowledge of North Korea's position on denuclearization confirmed to CNN the Kim regime could change its stance on its nuclear program, if the United States does not alter its policy on easing economic sanctions.
North Korea's foreign minister told the United Nations in September that continued sanctions were deepening its mistrust of the United States and there was no way the country would give up its nuclear weapons unilaterally under such circumstances.
The high-level North-U.S. talks had been set to take place in New York Thursday, a follow-up to Pompeo's fourth visit to Pyongyang last month.
The latest NY meeting was set to come ahead of a busy season of diplomacy, with Pompeo meeting senior Chinese officials in Washington on Friday.
But experts say North Korea's moves so far are largely cosmetic and easily reversible.