North Korean media mentioned a visit by a delegation from the South last week, but no coverage has been seen of Kim Jong Un's invitation to meet U.S. President Donald Trump or the South Korean president to discuss the future of Pyongyang's nuclear weapons programme.
The South Korean officials who carried Kim's invitation to Washington are visiting China and Japan this week to update state heads on the talks.
Just days after he stood outside the White House and announced the planned meet between the USA president and the North Korean leader, Chung Eui-yong was in Beijing to brief Xi and China's top diplomats on the fast-moving efforts to address the nuclear standoff.
Chinese President Xi Jinping (R) shakes hands with South Korea's National Security Office chief Chung Eui-yong in Beijing on March 12, 2018.
After the meeting last Friday (Korean time), the envoys said Trump agreed to hold a summit with Kim by May to achieve permanent denuclearization.
China is "on the same page" with Seoul over the issues of the Korean peninsula, President Xi Jinping said on Monday, a spokesman of South Korea's presidential Blue House said.
Chung left for China on Monday morning.
The two top diplomats "plan to share their assessment of the recent rapid progress on the Korean Peninsula and to have in-depth consultations on how to closely cooperate on denuclearizing the peninsula as well as on (envisioned) inter-Korean and US-North Korea talks", the Ministry of Foreign Affairs said.
President Moon Jae-in (center) talks with National Security Council chief Chung Eui-yong and National Intelligence Service chief Suh Hoon and others at Cheong Wa Dae on Sunday.
He underscored the importance of global efforts to pursue "political" and "diplomatic" resolutions.
"We have not seen nor received an official response from the North Korean regime regarding the North Korea-U.S. summit", Baik Tae-hyun, the spokesman of the South's Ministry of Unification, told a regular news conference.
The dramatic turn of events follows a flaring of tensions up until late previous year as the North continued its nuclear and missile tests despite strong condemnation from the worldwide community.