Satellite images taken over the weekend appear to indicate that North Korea is in the final stages of preparation for the nation’s sixth nuclear test.

38 North, a Washington D.C. based think tank that monitors intelligence out of North Korea released a report on Tuesday with evidence to suggest a good deal of activity at North Korea’s Punggye-ri test sight, including multiple vehicles and trailers at the scene and what appears to be communication cables being run from the site to a nearby test tunnel.

Water can be seen being pumped from the area and drained down the hill, which 38 North postulates is “presumably 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 imagery, however, does not provide any definitive evidence of either a nuclear device or the timing of a test.” The report states.