South Korean legislators briefed by the National Intelligence Service (NIS) said the work was taking place at the Tongchang-ri launch site, Yonhap news agency reported on Wednesday.
Satellite images seen by 38 North, a Washington DC-based North Korea project, showed structures on the launch pad had been rebuilt sometime between February 16 and March 2, Jenny Town, managing editor at the project and an analyst at the Stimson Center think-tank, told Reuters news agency.
The news comes days after a second summit on denuclearisation between Trump and North Korean leader Kim Jong Un broke down over differences on how far North Korea was willing to limit its nuclear programme and the degree of US willingness to ease sanctions.
South Korea’s JoongAng Ilbo newspaper cited unidentified legislators as saying NIS Director Suh Hoon told them the structures being restored at the launch site included the roofs and doors of buildings.
Suh was quoted as saying the move is seen as either preparation to restart long-range missile test-launches in the event that the nuclear diplomacy completely collapses, or to add structures to the launch site to blow up more dramatically in a show of denuclearisation commitment when US inspectors visit, if negotiations with Washington go well.
The offices of South Korean legislators who took part in Tuesday’s briefing couldn’t immediately confirm the newspaper report.
A US official speaking anonymously said the NIS was considered reliable on such issues, but added that the work described did not seem particularly alarming, and certainly not on a scale of resuming missile tests, which have been suspended since 2017.
The breakdown of the summit in Hanoi last week has raised questions about the future of US-North Korea dialogue.
US Secretary of State Mike Pompeo said on Monday he was hoping to send a delegation to North Korea in the coming weeks but he had had “no commitment yet”.
While North Korea’s official media said last week that Kim and Trump had decided at the summit to continue talks, its Vice Foreign Minister Choe Son Hui told reporters Kim “might lose his willingness to pursue a deal” and questioned the need to continue.
Yonhap also quoted legislators briefed by intelligence officials as saying the five-megawatt reactor at North Korea’s main nuclear site in Yongbyon, which produces weapons-grade plutonium, had not been operational since late last year, concurring with a report from the UN atomic watchdog.
Yonhap quoted the sources as saying there had been no sign of plutonium reprocessing from the reactor and that tunnels at North Korea’s main nuclear test site in Punggye-ri had remained shut down and unattended since their widely publicised destruction in May, which Pyongyang said was proof of its commitment to ending nuclear testing.
The fate of the Yongbyon nuclear complex and its possible dismantling was a central issue in the Hanoi summit.
Trump’s national security adviser said on Tuesday the United States will look at ramping up sanctions on North Korea if Pyongyang doesn’t scrap its nuclear programme.
“If they’re not willing to do it, then I think President Trump has been very clear … they’re not going to get relief from the crushing economic sanctions that have been imposed on them, and we’ll look at ramping those sanctions up in fact,” John Bolton told Fox Business Network in an interview.