Seoul says a suspected North Korean drone found near the Korean border last week was found to have taken photos of a US missile defense shield in the South.

Seoul’s Defense Ministry said on Tuesday investigators discovered hundreds of photos from the drone’s Sony-made in-built camera.

The Ministry says they include 10 photos of US missile launchers and a radar system installed in the southeastern town of Seongju earlier this year. It says the rest are mostly photos of residential areas, farming fields and other less-sensitive areas in the South.

Drones are a relatively new addition to North Korea’s arsenal. In 2014, several other suspected North Korean drones were found south of the border and experts said they were low-tech but could be considered as a potential security threat.