A spokesperson for the White House National Security Council said the "national security advisers committed to continue coordinating closely."

Bolton also met separately with his Japanese counterpart, Shotaro Yachi.

"Ambassador Chung and Secretary General Yachi are the first national security advisers to meet with Ambassador Bolton since he assumed the role of US National Security Adviser" on Monday, the spokesperson said in an email to Yonhap.

Chung traveled to the US capital last month shortly after his meeting with Kim in Pyongyang. He conveyed the North Korean leader's desire to hold a summit with Trump as soon as possible, along with his commitment to the denuclearization of the Korean Peninsula.

Trump accepted the invitation on the spot.

Seoul has called for a "comprehensive and phased"

denuclearization deal with Pyongyang, while Bolton has advocated a so-called Libyan style solution that would reward the regime only after it completely dismantles its nuclear weapons program.

According to one source, Seoul expressed its wish to arrange a meeting between Chung and Bolton soon after the latter took office and to establish a direct communication channel between the two to coordinate preparations for the summits.

The appointment of Bolton, known for his hawkish views, raised concern the US could consider military action against Pyongyang should the summit go wrong. The former US ambassador to the United Nations recently argued for a preventive strike on North Korea, although he also said it is not his favored option.

Seoul is adamantly against any armed conflict on the peninsula.

In Washington, South Korean Ambassador to the US Cho Yoon-je and Susan Thornton, acting US assistant secretary of state for East Asia, plan to hold regular summit-related meetings starting next week. (Yonhap)