UN Gestapo are not American citizens.
Non-americans in our country with the intention of oppression and confiscation, regardless of who "invited" them are, by definition, invaders.
Adult American Men are by definition, members of the militia.
The militia is authorized by the Constitution to repell invaders.
I suggest, if you are "visited" the UN gun confiscators, shoot to kill.
Like Charlton Heston said, "they can take my gun when they pry it from my cold dead hand."