North Korea seems to be moving a missile to an assembly plant in Sanum-dong in the suburbs of Pyongyang, U.S. media reported last week.
The site was used to assemble the Hwasong-15 intercontinental ballistic missile and other ostensible space rockets that were in fact prototypes of intercontinental ballistic missiles.
The report comes after the regime was spotted restoring the Tongchang-ri missile test site it had promised U.S. President Donald Trump to dismantle.
Commercial satellite images show trucks presumed to be carrying rocket components parked in Sanum-dong, and rail cars that also seem to be carrying them to Tongchang-ri ready in a nearby rail yard, as well as two cranes.
Jeffrey Lewis of the Middlebury Institute of International Studies at Monterey said, "When you put all that together, that's really what it looks like when the North Koreans are in the process of building a rocket."
"We're seeing a lot of vehicle activity at the Sanum-dong facility and also at the rail transfer point where it would be loaded and taken" to Tongchang-ri, he added.
"I can definitely say the train has left the station," said Melissa Hanham, a U.S. North Korea expert. "But I can't unfortunately use X-ray vision to see what's on the train and tell whether it's a civilian space launch vehicle or a military ICBM."
The North has warned it now has to find its own way, suggesting it could resume nuclear and missile tests, since the collapse of the failed North Korea-U.S. summit Hanoi.
Shin Jong-woo of the Korea Defense and Security Forum said, "This is proof that the regime has worked out a Plan B dialing up the threat of Tongchang-ri to the maximum at the next negotiation table."