The second deputy director of South Korea's National Security Office Kim Hyun-chong says talks with the U.S. on resuming denuclearization dialogue with North Korea and the upcoming South Korea-U.S. summit went well.

Kim, who held talks with  U.S. Deputy National Security Adviser Charles Kupperman at the White House on Monday to fine-tune details of the summit agenda, spoke to South Korean reporters before boarding his flight back home from New York on Wednesday.

He said negotiations on Pyongyang's denuclearization must continue and that it's important for Seoul to maintain the dialogue momentum through the current top-down diplomacy.

Kim declined to comment on the prospect of Seoul sending a special envoy to Pyongyang ahead of President Moon Jae-in's summit talks with U.S. President Donald Trump in Washington on April eleventh.

The deputy director added that there were no discussions about resumptions of inter-Korean projects, such as the Mount Geumgang tourism program or the Gaeseong industrial park on the summit's agenda. 

When asked about talks regarding U.S. sanctions on the North, Kim said the sanctions will remain in place.