Lee's visit, days after the February 27 and 28 Kim-Trump summit, came as Seoul struggles to maintain its role prodding along North-U.S. dialogue.
The US side has included North Korea's chemical and biological weapons in the negotiations with Pyongyang.
Images released last week by Beyond Parallel - part of the Washington-based Center for Strategic and International Studies - showed that North Korea was rebuilding a long-range rocket site at the Sohae Launch Facility.
For North Koreans who defect, the South's electoral system was "definitely novel", said Sokeel Park, of campaign group Liberty In North Korea.
Any launch would send the stuttering talks on denuclearisation into disarray, after a high-stakes second summit between Donald Trump and Kim Jong Un collapsed last month without a deal. "I'm not going to speculate on what that particular commercial satellite picture shows".
Snow and ice warning for Preston from Sunday evening
Lasting from 6pm today until 6am on Tuesday, 25mm of rain is expected to accumulate as heavy brain rain turns to squally showers. Temperatures are not likely to get much above 10 or 11C - but with the wind chill, this could feel more like 6 to 8C.
"The secretary and the president have been very clear that they remain open to the dialogue". The North Koreans for example, have pledged to give up their nuclear weapons program at least five separate times, beginning in 1992 with the joint North/South de-nuclearization agreement. "And one mistake that prior administrations made repeatedly was assuming that the North Koreans would automatically comply when they undertake obligations", Bolton said.
North Korea held first parliamentary polls in 2014, under the leadership of Kim Jong-un, in which 99.97 percent of all listed voters had contributed.
A former Unification Ministry official here said, "It is a confession of the difficulty caused by a failure to get the U.S.to ease sanctions during the Hanoi summit".
He added, "We see exactly what they're doing now. I would be surprised, in a negative way, if he did anything that was not per our understanding", Trump told reporters as he left the White House on Friday to survey damage in Alabama.
North Korea has frozen nuclear and missile testing since 2017, and Trump has pointed to this as a positive outcome from almost a year of high-level engagement with North Korea.
North Korean leader Kim Jong-un said last week that there's no more urgent task than developing his country's economy and improving its people's lives. "The president has been clear on that", Stephen Biegun, the special USA envoy for North Korea, said at a forum hosted by the Carnegie Endowment for International Peace in Washington.
Soviet-style Communist states had a long tradition of holding general elections, he said, even if the ruling party ignored its own rules about holding regular congresses - something the North skipped for more than 30 years.