More evidence has emerged of significant activity at North Korea’s shuttered Punggye-ri nuclear test site, as the country continues repair work at the facility that would allow it to conduct its seventh atomic test.

Satellite imagery taken earlier this week has shown the construction of new buildings, movement of lumber and an increase in equipment and supplies immediately outside a new entrance to Tunnel No. 3, indicating that construction work is likely happening both inside Tunnel No. 3 and outside in surrounding areas.

The Punggye-ri site was closed in 2018 — with some tunnels blown up — after leader Kim Jong Un announced a self-imposed moratorium on nuclear and long-range missile tests amid denuclearization talks with the U.S. In January, Kim effectively signaled that his country is no longer bound by that moratorium.