Russia's recruited so many inmates to fight in Ukraine that it's shuttering some of its prisons

• Russia's prison population has been plummeting as more inmates get recruited to fight in Ukraine.
• A local official said on Thursday that some prisons would be closed to "optimize and save money."
• Russia's military has been relying on prisoners to plug its manpower gaps.

Russia has tapped on so many inmates to fuel its war effort in Ukraine that it's closing down some prisons, a local official said on Thursday.