Rep. Andy Kim, a Korean-American Democrat from New Jersey, said the U.S. should be prepared to make concessions to North Korea, including temporary sanctions relief, to advance the North's denuclearization.

At a webinar hosted by the George Washington Institute for Korean Studies on Monday, Kim said the U.S. should think about what it is willing to do going forward, while recognizing that some steps from the past haven't been working.

Kim also said President Moon Jae-in needs to put forth exactly what options are on the negotiating table after the two-year dialogue impasse, when he meets with U.S. President Joe Biden in Washington next month.

He expressed hope that Moon will come to Washington with a greater level of detail and clarity, adding that is why the upcoming summit will be so important.

The Biden administration is finalizing a comprehensive review of its North Korea policy, in consultation with South Korea and Japan.