A US think tank says significant expansion work is still being carried out inside a satellite launching station that is located in the northwestern part of North Korea. Pyongyang apparently wants to be able to fire larger and more capable rockets from that site.

The Center for Strategic and International Studies on Thursday released satellite photos of the Sohae Satellite Launching Station at Tongchang-ri. The pictures were taken on September 6.

The center says the images show that the focus of the work is the expansion of "fuel storage capacity at the launch pad." It says the North's goal is to acquire the ability to launch "larger and more capable space launch vehicles."

The think tank says "it is extremely unlikely that a new satellite launch will be conducted from the launch pad in the immediate future." It cites the ongoing construction work as a reason.

A long-range ballistic missile was launched from the station in 2016. But, Pyongyang claimed it had fired an earth observation satellite.

The ruling party newspaper, Rodong Sinmun, has reported that the country's leader Kim Jong Un inspected the station in March.

He ordered workers to refurbish and expand the facility at that time, so large carrier rockets with military reconnaissance satellites could be launched from it.