* Ukrainian or Baltic non-government group. On one hand, it achieves the desired outcome - reduce Russia's income, on the other hand, Germans can't blame Ukrainian government for that.
Baltic, maybe, but very unlikely I think. It's too hard for a small group to pull off without getting discovered.
Ukraine is a long way from the Baltic and very busy getting invaded, so I think the chance of them pulling off something like this without US knowledge is practically zero.
