CHERNOBYL, Ukraine (AP) Here in the dirt of one of the worlds most radioactive places, Russian soldiers dug trenches. Ukrainian officials worry they were, in effect, digging their own graves.

Thousands of tanks and troops rumbled into the forested Chernobyl exclusion zone in the earliest hours of Russias invasion of Ukraine in February, churning up highly contaminated soil from the site of the 1986 accident that was the worlds worst nuclear disaster.

For more than a month, some Russian soldiers bunked in the earth within sight of the massive structure built to contain radiation from the damaged Chernobyl nuclear reactor. A close inspection of their trenches was impossible because even walking on the dirt is discouraged.

As the 36th anniversary of the April 26, 1986, disaster approaches and Russias invasion continues, its clear that Chernobyl a relic of the Cold War was never prepared for this.

With scientists and others watching in disbelief from afar, Russian forces flew over the long-closed plant, ignoring the restricted airspace around it. They held personnel still working at the plant at gunpoint during a marathon shift of more than a month, with employees sleeping on tabletops and eating just twice a day.