Chernobyl has been abandoned since the world’s worst nuclear disaster here three decades ago. But with tens of thousands of Russian troops amassing on Ukraine’s border with Belarus just a few miles away, the ghost town is now playing host to security forces training for war. Ukraine is using Chernobyl to prepare for another potential cataclysm.

Russian President Vladimir Putin has consistently denied that the Kremlin is planning an incursion into Ukraine. Russia’s deployments in Belarus are ostensibly linked to joint exercises due to begin on Thursday. However, satellite photographs show Russian camps being established close to the border with Ukraine, hundreds of miles from where the exercises are taking place.

If Russia were to invade Ukraine, the Chernobyl Exclusion Zone is a possible conduit to Kyiv. American and NATO officials say President Putin is steadily increasing his military presence in Belarus from 5,000 troops in January to an estimated 30,000 sometime this month.