Both the launch pad and engine test stand were in about the same condition since last August, according to the 38 North report.
Two Washington-based groups that follow North Korea say some structures at the launch site have been rebuilt in the past three weeks.
The respected Washington-based 38 North project, another independent research website specializing in North Korea, also reported building work at the Sohae facility, based on commercial satellite imagery.
Director General Yukiya Amano told the agency's board members on Monday that the IAEA has not observed any indications of the operation of the five-megawatt reactor at the Yongbyon nuclear complex since early December of past year. He added that North Korea is continuing work on an experimental light-water reactor at Yongbyon.
U.S. National Security Adviser John Bolton reiterated on Tuesday that North Korea will not "get relief from the crushing economic sanctions that have been imposed on them" unless they dismantle their nuclear weapons program and "everything associated with it".
"The danger here is that we could start spiraling downward as each side takes steps and undermine the process that's been in place since last spring". The Beyond Parallel project is headed up by Victor Cha, who was once a candidate to become US ambassador to South Korea but was withdrawn from consideration after disagreeing with the Trump administration's North Korea policy. Trump did so in his first meeting with Kim last June in Singapore as well. He said Kim demanded all sanctions on North Korea end at once in exchange for closing down the Yongbyon nuclear facility. -North Korean summit in Hanoi, and relayed Japan's stance over the issue to Kim at Abe's request.
David Albright is the president of the Institute for Science and International Security and a former nuclear weapons inspector.
He also said that it was "too early to see" what exactly was going on in North Korea.
Its dismantling of parts of the Tongchang-ri facility occurred at the beginning of U.S.
Olli Heinonen is a former deputy director of the International Atomic Energy Agency.
North Korea did not, however, allow experts to witness the dismantlement of the site and verify what actually happened.
This site in particular was one that Kim had assured the South Korean president that he would "permanently dismantle" in September.
"Aside from the fact that (North Korea) has never tested an ICBM from Sohae - it's a space vehicle launch site - preparation for any launch would require a wide range of activities not observed in the imagery", Wit said.
But CSIS said building activity is now "evident" at the Sohae Satellite Launching Station, from where Pyongyang launched satellites in 2012 and 2016.