Kim Myong-gil made the remarks in Beijing on his way back home after holding working-level denuclearization talks with his US counterpart, Stephen Biegun, in the Swedish capital of Stockholm on Saturday, warning that a "terrible" incident could happen if the negotiations don't go well, reports Yonhap News Agency.
"It's up to the US whether to hold talks later on," Kim told reporters.
"Ask the US whether to continue talks... If the US is not well prepared, who knows what terrible incident could happen. Let's wait and see."
Asked if the two sides could sit down again "in two weeks" as suggested by the US in the wake of the Stockholm meeting, Kim voiced scepticism, saying that Washington has failed to come up with a new proposal and that he does not believe it will prepare one in such a short period of time.
Following Saturday's talks, Kim told reporters that the talks broke down due to the failure of the US to come up with a new proposal.
Contradicting Kim's remarks, Washington said the two sides had "good" discussions and that it had accepted Sweden's invitation to return to Stockholm in two weeks to continue negotiations with the North.
On Sunday night, an unnamed spokesman of the North's Foreign Ministry issued a statement, saying that Pyongyang does not have any willingness to talk with the US again until Washington takes "practical measures for complete and irreversible withdrawal of hostile policy against" it, Yonhap reported.
The spokesperson also urged the .S to come up with a new calculation method before the end of this year, a deadline that North Korean leader Kim Jong-un imposed in his speech in April.
Saturday's talks marked the resumption of nuclear negotiations that had been stalled since the no-deal Hanoi summit between Kim Jong-un and US President Donald Trump in February.
The summit collapsed as they failed to meet halfway over how to match Pyongyang's denuclearization and Washington's sanctions relief.
( With inputs from IANS )