Satellite images viewed by CNN showed that the Yeongjeo-dong missile base and a nearby, previously unreported site were not only active but were being upgraded.
Despite that site being known to the USA intelligence community, images show in the past year, North Korea has significantly expanded to a nearby base. Trump lashed out at the New York Times, calling the newspaper's report about North Korea's missile bases "fake news".
The images indicate North Korea was building a large underground facility in 2017 and it was still under construction in August 2018.
Trump said on Saturday that he hoped to organize a second summit with Kim in early 2019.
"Whatever [North Korean leader Kim Jong Un] says about his desire for denuclearization, North Korea continues to produce and deploy nuclear armed missiles", the Middlebury Institute's Jeffrey Lewis told CNN.More news: Dow Jones falls almost 800 points amid trade war, recession fears
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"It is one of North Korea's major facilities that the military has tracked and monitored in coordination with the U.S. forces", said Joint Chiefs of Staff's spokesperson Col. Roh Jae-chun.
During the talks, Kang and Pompeo will discuss issues of mutual concern, including a joint strategy on North Korea, according to South Korean Foreign Ministry spokesman Noh Kyu-duk. "They have not lived up to the commitments so far", he told The Wall Street Journal's annual CEO Council conference.
An official at Seoul's presidential Blue House who spoke to JTBC on the condition of anonymity said the South needs an answer by the weekend in order to make plans for a summit, if it is to happen before the end of the year.
National Security Advisor John Bolton said Tuesday that Trump thinks the North Korean strongman hasn´t met the commitments he made at the Singapore summit.
Pence spoke days after the release of additional new commercial satellite images identifying more than a dozen undeclared North Korean missile operating bases, another sign that Pyongyang is continuing to move forward with its ballistic missile program. "These shelters are similar to the ones seen at the older portion of the Yeongjeo-dong base".