It's been nearly three years since the Russian invasion of Ukraine, and there is no sign that Vladimir Putin's war machine is letting up, despite huge losses on both sides.

And while armies may march on their stomachs, as the saying goes, they can't actually shoot without cotton.

That staple commodity is used to make gunpowder and explosives, and Russia has a steady

supply from one of its former Soviet republics. Special correspondent Simon Ostrovsky investigated

why that is and who's trying to stop it.

One year ago, a powerful explosion tore through Tashkan, the capital of Uzbekistan,

an authoritarian country that's Russia's top supplier of nitrocellulose, a substance used in

the production of gunpowder and explosives Russia needs for its war in Ukraine. The blast was so powerful it could be felt 18 miles away, according to local media reports.

It left a teenager dead, 163 others injured, and some 600 Tashkent residents damaged.

The date of the explosion, September 28,

2023, coincided with the visit of Michael Corrilla, a high-ranking commander in the U.S.

military.

Thank you all for your attendance here today.

General Corrilla, who is the chief of U.S. Central Command, had just departed Uzbekistan

after holding meetings with Uzbek

defense officials, leading to speculation that the blast had something to do with him.

But there's an alternative explanation, and it comes from a couple thousand miles away.

My sources in Ukraine tell me they have a theory about what might have happened, and it ties

back to Russia's war.

So I've come to Kiev to see if I can find out more.

Ukraine's security services are acutely aware of the fact that Russia produces much of its

gunpowder propellants from this.

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