North Korean workers are clearing a swath of a mountain directly opposite South Korea on the east coast, a video taken by NK News reveals, in what may be construction for an observation post or other military installation.

The video captured on Tuesday from the Goseong Unification Observatory near the Demilitarized Zone shows workers who appear to be wearing military uniforms standing in an area stripped of trees on the side of the mountain.

The North Korean soldiers’ activity comes amid increased scrutiny of both Koreas’ efforts to bolster military readiness around the border after ROK media reported that t