Don't get me started on this topic.
Such behavior means the intended violation of the sovereignity of another state. If it is conducted without cooperation and/or knowledge of the target state, it means an act of war in my eyes. Attacking agents, no matter if american or Israeli or Belgian or Kenian ones, would - if being caught - get courtmartialed and executed on the basis of martial law and what it has to say on combatants not wearing uniforms, if it were up to me. No american agent from any of the american services has any right to enforce Ameeican laws on german/European/foreign streets, and if american law says somethign different, it still is only valid for the nation of the US, not Europe or any other nation worldwide.
US laws may not be permitted to overrule other nations laws, and the validity of US laws ends where the sovereignity of other nations begin - at the latest. Not accepting this is megalomania, arrogance, and an act of war - simply this. The world is not the rest of America. Bounty hunters may have been a tradition in the Wild West, but if they leave the Wild West and operate outside the Us, they are just gangster and criminals, needing to be locked away, or put down. f they are acting on behalf of orders from American authorities and offices, in my eyes they are commiting an act of war. And that means courtmartialing them for me (like spionage and sabotage in general is an issue not for civil courts, but military courts, since it is about attacks of one country on another). Interestingly, a longer while ago, one judge of the German constitutional court, once argued the same way on TV.
Tell Amercia that the Russians from now on, or the Danes, or Australia claims such rights in return, and attack America's sovereignity that way - and imagine what colourful, nationalistic reactions from america you would get immediately. America claims that right for itself only becasue it thinks america is allowed to do it, and it is allowed to do it becasue it is America. And that is a definitely too rich.