North Korea's "long-range missile bases expanding, even as a second summit with president Kim is in the works", Tapper said.
The satellite imagery offers evidence that the Yeongjeo-dong missile base and a nearby, previously unreported site remain active and have been continuously upgraded, underscoring the reality of just how far apart Washington and Pyongyang are on the issue of denuclearization despite five months of sporadic talks.
While the base at Yeongjeo-dong has always been known to USA intelligence agencies and analysts, researchers at the Middlebury Institute of International Studies at Monterey told CNN that the images reveal construction on a new facility just seven miles away from the older site that had not been previously publicly identified.
"Satellite images show that the base remains active", an institute report states, CNN reported.
China is the North's most important economic and political partner, but has signed on to United Nations economic sanctions aimed at pressuring leader Kim Jong Un to abandon his drive to develop nuclear weapons and the ballistic missiles to deliver them.
The site's location makes it a strong candidate to receive North Korea's newest long-range missiles, including those that can carry nuclear weapons, according to Lewis and colleague David Schmerler, CNN reported.
But National Security Adviser John Bolton said Tuesday that there should be another summit with Kim.
U.S. officials have insisted North Korea must fully disarm and open itself to global inspectors before it will grant sanctions relief while North Korea's state media has called the stance a "hostile policy" and said the USA "is responding to good faith with evil".
The State Department declined to comment to the news outlet.