what does this mean? let's bring in cnn's paula hancock live from seoul. what does this mean that we detected this digging? >> reporter: well, dave, this means according to the u.s. defense official that it may mean a nuclear test from north korea is not as imminent as previously thought. basically from this satellite imagery they've been able to tell there's more digging at the entrance 2001 of the tunnels where these underground nuclear tests would take place so they are assuming that could mean they have more work to do although we've heard from 38 north the u.s. tracking group that they believe they are primed and ready tore nuclear test number six. all that's lacking is the green light from the north korean leader kim jong-un. but it's when not if number six will happen. here in south korea the elements of thaad the u.s. missile defense system are now being putting in place in the location where they will be deployed. they were moved in the cover of dakness. many protesters, local residents