Satellite images taken this week suggest North Korea could be in the final stages of preparations for a new nuclear test, US-based analysts said Tuesday.
The images, taken March 25, show up to four vehicles or equipment trailers continuously present at the entrance to the Punggye-ri Nuclear Test Site, with communications cables likely laid on the ground.
"This equipment would likely be used to initiate the test, collect data from the explosion and process the data," said 38 North, a project of the US-Korea Institute at Johns Hopkins University.
The researchers noted that water was being pumped out of the portal and drained downhill to keep the tunnel dry for monitoring or communications equipment.
"The combination of these factors strongly suggests that test preparations are well under way, including the installation of instrumentation," the researchers said.
Last week, the US military had reached similar conclusions after observing activity at the hermit state's nuclear sites.
North Korea is on a quest to develop a long-range missile capable of hitting the US mainland with a nuclear warhead, and staged two nuclear tests and multiple missile launches last year.
Despite a string of United Nations sanctions since it first tested a nuclear device in 2006, Pyongyang has insisted it will continue its program.