New activity detected at North Korea's Punggye-ri nuclear test site

SEOUL, Sept. 25 (UPI) -- North Korea's nuclear test site showed new activity that could mean Pyongyang is preparing for a nuclear test, but Seoul's Unification Ministry said Friday there are no "imminent signs" of testing.

Satellite images from Sept. 18 analyzed on 38 North, a Johns Hopkins University website dedicated to North Korea issues, indicated new movement at the Punggye-ri Nuclear Test Site's West Portal Area, where nuclear tests took place in 2009 and 2013.

Near a tunnel that was begun in May 2013, four large vehicles were parked adjacent to its entrance and next to spoil cart tracks that are used in mining carts to carry away debris during tunnel digging. The tunnel's entrance was covered with camouflage netting that was being used to hide activity, according to analysts Jack Liu and Joseph S. Bermudez, Jr.

The satellite images also showed a large number of vehicles at the Guardhouse Checkpoint that lead to the West Portal, a new development since Sept. 7, when the site showed little to no activity despite the completion of new buildings and ongoing tunnel maintenance.

In the South Portal Area, an area in front of a tunnel that was dug before 2012 had been widened and "graded," with differently colored sand or gravel used to grade or mark the surface. Vehicles and equipment doing the grading were nearby, according to the analysis. Erosion control is important to the site, the analysts wrote, because otherwise the only road that runs to the nuclear site could be washed away.

South Korea's Unification Ministry said the government is aware of the most recent satellite images of Punggye-ri and the detection of new activity but said there are no "imminent signs" of a fourth North Korea nuclear test, Yonhap reported.

"We are closely watching trends related to [nuclear testing activity]," ministry spokesman Jeong Joon-hee said Friday.