A U.S. think tank says new activity has been detected at North Korea’s Sohae Satellite Launching Station in Tongchang-ri.

Satellite images taken September 27 show rail-mounted shelters, trucks and cranes near the vertical engine test stand, with signs of drainage work also visible, according to the CSIS Beyond Parallel program.

Analysts said the activity may indicate preparations for a new rocket engine test, though routine maintenance cannot be ruled out.

The site is where Pyongyang has previously launched long-range rockets and reconnaissance satellites.

CSIS noted the construction of new infrastructure, including an L-shaped pier, suggesting North Korea is building capacity for larger space launch vehicles.

It added that heavy investment at the site underlines Kim Jong-un’s determination to pursue additional satellite launches for security and prestige.