I know a version that is a little different. It glorifies the kids bombing more. It goes,

In a bombed out garret, so lowly and so mean,
Oh smell the pungent odor of nitroglycerin.
Three busy little children are filling cans with nails,
They're busy making fuses as they sing this mournful wail -

Oh, freedom, freedom, we'll live to see the day,
Freedom, freedom, a child shall lead the way.

"Let's draw straws to see whose turn it is to throw the bomb-"
Johnny's hand is trembling, he's trying to be calm -
Polly's face is ghostly white, she's gripping Johnny's arm,
The last to take for freedom's sake is little brother Tom

There are a few more verses. The kids in this one don't seem to be Slavic, from the names. Does anyone know this version? I'd love to know what book it might be in!