The chief nuclear negotiator of the Democratic People's Republic of Korea said on Tuesday that dialogue between Pyongyang and Washington is "impossible" unless the United States makes a bold decision and drops its hostile policy against the DPRK.

Kim Myong-gil made the remarks in an interview with the state's Korean Central News Agency, adding that the DPRK has "already reiterated its stance for many times".

Kim's interview counts as the fourth instance within 24 hours that the DPRK sought to exert pressure on the US.

Also on Tuesday, senior DPRK official Kim Yong-chol said the US must completely scrap all joint military drills between it and the Republic of Korea, and abandon its hostility to the DPRK if it wants to see the resumption of nuclear negotiations.

On Monday, a former chief nuclear envoy of the DPRK, Kim Kye-gwan, issued a statement that Pyongyang is no longer interested in holding another summit with Washington, arguing that Pyongyang gained "nothing" from their previous meetings.

Hours later, the Korean Central News Agency carried a separate statement that the US "should not even dream of having negotiations with the DPRK" before dropping its "hostile policy" against Pyongyang.

Last week, the DPRK's Foreign Ministry said the differences between the two sides won't be addressed with minor concessions, such as the opening of a liaison office in each country.

Wang Junsheng, an associate researcher at the National Institute of International Strategy under the Chinese Academy of Social Sciences, said that the DPRK, by releasing a series of statements stressing its stance ahead of the resumption of nuclear talks, is aiming to increase the pressure on the US.

"From the DPRK's statements, we can see signs that they want the US to get to the more substantive issue of denuclearization, and though it's not explicitly stated, what they really hope to see is Washington's sanctions relief. Other actions are seen as coming nowhere near this core concern," Wang said.

After the second summit between US President Donald Trump and the DPRK's top leader Kim Jong-un collapsed without a deal in February, the DPRK warned that it will seek a "new way" unless Washington comes up with a new proposal by the end of this year.

The US and the DPRK held their last working-level talks in Stockholm in early October, but the meeting ended without much progress and Pyongyang accused Washington of failing to come up with a new proposal.

The ROK and the US announced on Sunday the postponement of joint air exercises that had been set for later this month in a move at backing the diplomatic efforts. However, Pyongyang said it wants the military drills stopped completely.