▲ Satellite image of Tunnel 3 at Punggye-ri Nuclear Test Site
The US Center for Strategic and International Studies (CSIS) said that while the maintenance of Tunnel 3 of the Punggye-ri nuclear test site, which is expected to be used in the event that North Korea conducts its 7th nuclear test, has been completed, new construction activities are also observed in Tunnel 4.
CSIS's website specializing in North Korea published this analysis based on satellite images.
According to the report, the maintenance work of Tunnel 3, which started about four months ago, has been completely completed.
However, in the report, wall construction and construction materials were newly discovered near the entrance to the tunnel No. 4.
This is an effort to revitalize the tunnel, which was 'disabled' in 2018 for further nuclear tests in the future, CSIS analyzed.
The Punggye-ri nuclear test site has four tunnels, and no nuclear tests have been carried out in the third or fourth tunnels.
Tunnel 1 conducted the first nuclear test in 2006, and Tunnel 2 carried out the 2nd to 6th nuclear tests, respectively.
North Korea declared a nuclear test and intercontinental ballistic missile (ICBM) moratorium in 2018 ahead of the summit between the two Koreas and North Korea, and also bombed the tunnels of its nuclear test site.
However, it was observed that only the entrance to the tunnel was blocked at the time, and it was not confirmed whether the interior was also destroyed.
(Photo = CSIS homepage capture, Yonhap News)