Satellite images show activity at a missile base in North Korea

Despite diplomatic efforts by the U.S., new satellite images show that North Korea has expanded an unidentified long-range missile base along the "mountainous interior of the country," CNN's Zachary Cohen reports.

Why it matters: The construction does not technically violate any agreement between the U.S. and South Korea, per CNN. However, the activity shown from the images is more evidence that the Yeongjeo-dong missile base and a nearby site remain active, leading the Trump administration to conclude that Pyongyang has failed to live up to its promises.

The details: The images show the country was building a large underground facility in 2017, which was still under construction as of August.

• In November, satellite imaging revealed North Korea had been making improvements to 16 hidden ballistic missile bases even as it has made halting moves to dismantle a major site to appease the U.S.
• Secretary of State Mike Pompeo met Kim in Pyongyang in October to prove that the Punggye-ri nuclear test site had been "irreversibly dismantled."

What to watch: National security adviser John Bolton said Tuesday that Trump wants to hold a second summit meeting early next year with North Korea even though Kim has not met promises to start dismantling his nuclear weapons program.