North Korea renovated a major political prison in the country’s remote northeast during the pandemic, NK Pro analysis shows, in what one expert described as likely part of preparations for an influx of prisoners.

High-resolution Google Earth satellite imagery reveals that North Korea constructed new buildings and upgraded security infrastructure at Kwalliso No. 25, also known as the Chongjin concentration camp, between 2020-2023.

The renovations began in 2020 when authorities built a 1476 square foot (450 square meter) structure within the walls of the prison camp. A building outside of the main detention facility was reconstructed the same