The new drone attack inside Russia is no surprise since Ukrainians freely went to work in Russia with no visa until this year. I knew Ukrainian people in Uman that  went to work in Russia. The border was open in both direction until recently..   I even knew of a sad case where someone  in Uman [Ukraine] was a travel agent and arranged trips for a large gathering and then simply took all the money and disappeared into Russia. Or so he thought, until some of the people he had cheated tracked him down. I forget how that ended, but for sure the cheater was not served tea and cookies