South Korea's top nuclear envoy said that the most important thing for the U.S. and North Korea is to meet again to continue negotiations after the breakdown of their second summit in Vietnam. 

Lee Do-hoon, special representative for Korean Peninsula Peace and Security Affairs, made the remarks to reporters on Tuesday after arriving at Dulles International Airport for a three-day visit to Washington. 

Lee said that he plans to listen carefully to the U.S. assessment regarding the outcome of the Hanoi summit and how it plans to move forward, adding he also intends to discuss ways to strengthen cooperation between Seoul and Washington. 

Meanwhile, the U.S. State Department said on Tuesday that Lee will meet with his U.S. counterpart Stephen Biegun in Washington on Wednesday. 

State Department spokesperson Robert Palladino also confirmed that Biegun will meet with his Japanese counterpart Kenji Kanasugi on Wednesday. 

According to diplomatic sources in Washington, the top envoys of South Korea, the U.S., and Japan will hold a three-way meeting on Wednesday. 

Lee departed for the U.S. for a three-day trip on Tuesday and plans to meet with Biegun and discuss the next steps regarding the North.