The "top-down" nuclear diplomacy that US President Donald Trump has employed toward North Korea may not be retained if Democratic presidential candidate Joe Biden wins the November election, Seoul's top envoy in Washington has said.

During a video-linked parliamentary audit Sunday (Washington time), Ambassador Lee Soo-hyuck made the remarks in response to a lawmaker's question about the possibility of a change in the US approach to the North following the Nov. 3 presidential vote.

"Those who would take charge of diplomatic and security affairs (should Biden win the election) are those who held high-level positions under the past Obama administration," the ambassador said.

"If the past is any guide, I expect that they will more likely be taking the form of conducting reviews at the low levels and then making recommendations, with the president giving his approval rather than employing a top-down approach," he added.

Lee then forecast that if Trump wins reelection, the leader-to-leader approach to the North would continue or be further strengthened.

Trump has stuck to the top-down approach with North Korean leader Kim Jong-un in apparent hopes of striking a denuclearization agreement in a more swift, comprehensive manner -- in a departure from the bottom-up approach that critics said was inefficient and time-consuming.

But skepticism has emerged as negotiations between Washington and Pyongyang have stalled, while the recalcitrant North has continued to develop seemingly longer-range, more refined ballistic missiles and other weapons systems as showcased during a military parade Saturday.

Commenting on the prospect of the nuclear negotiations under the Biden administration, the ambassador said that with Washington likely to focus on domestic and China issues, the Korean Peninsula issue could be treated as a "secondary" one.

"Candidly speaking, whether the Democratic Party or Republican Party, (Washington) has little room to pay attention to foreign policy," Lee said.

Touching on South Korean President Moon Jae-in's renewed push for the declaration of a formal end to the 1950-53 Korean War, Lee said the US government has responded positively to that proposal.

"The US' response is that the end-of-war declaration is sufficiently worth a consideration," he said. "The atmosphere in the US is that as long as it does not entail any legal meaning, it is meaningful for concerned countries to make the political declaration."

The ambassador added that the declaration would be possible should the North agree to it.

"I am not to say that if the end of war is declared, the nuclear weapons will be abandoned like a magic wand," he said.

"But as it could have significant meaning for the denuclearization process, the US shares this understanding, and we are waiting for the North's understanding."

With regard to Seoul's position on the growing US-China rivalry, Lee said, "Just because South Korea chose the US 70 years ago doesn't mean it has to choose the US for the next 70 years too," stressing that the country's national interests should be put ahead of anything else in making such choices. (Yonhap)