South Korea's top nuclear envoy is now in Washington, seeking ways to mediate between the U.S. and North Korea and revive their stalled dialogue.

Arriving at Dulles International Airport in Washington on Sunday, Lee Do-hoon, special representative for Korean Peninsula peace and security affairs, told reporters that he will discuss the issue of putting an official end to the Korean War with Washington officials. 

[Sound bite: Lee Do-hoon - Special Representative for Korean Peninsula Peace and Security Affairs (Korean/English translation)] 
(Reporter: "Are you going to discuss the war-ending declaration? Experts at think tanks here are not positively responding to the idea.")
"The purpose of the current visit is to discuss all related matters, and of course, the issue of signing a war-ending declaration will be discussed. As you know, there were many occasions when the U.S. took interest in and reviewed the idea of officially ending the Korean War. Before concluding that this will or will not work, I expect to find common ground when we discuss the issue face to face."

In his UN speech earlier this month, South Korean President Moon Jae-in called for global support for a formal declaration to end the Korean War. However, his initiative met criticism in the wake of the recent killing of a South Korean fisheries official by North Korea.  

During his four-day trip, Lee will meet with U.S. Deputy Secretary of State Stephen Biegun, who doubles as the point man for North Korea.