U.S. National Security Advisor Jake Sullivan said Friday the U.S. is prepared to engage in diplomacy to make step by step progress towards the ultimate goal of denuclearization, but North Korea remains unresponsive.

Sullivan described the Biden administration's North Korea policy as such during a forum hosted by the Council on Foreign Relations, a New York-based think tank.

He said the policy is trying to land in between the different strategies of the two previous U.S. administrations, saying the Obama era adopted strategic patience while Trump pitched all-for-all, the grand bargain.

Sullivan said the U.S. continues to indicate to North Korea both directly and publicly, as he was doing at the time, that Washington is prepared to engage to try to make progress against the basic points that were laid down in the 2018 Singapore summit.

He said the U.S. also continues to carry out sanctions and closely coordinate with South Korea and Japan. 

Noting the regime not responding to overtures, Sullivan said the U.S. has not gotten traction in diplomacy with Pyongyang over the course of this year.