I trust from the "outside the US" precision in your inquiry that you are are aware of Posse Commitatus and are looking for something else.

I'm curious, outside the US, which laws are we talking about enforcing? The jurisdictional issues would seem to be ripe for "restrictions," whether to MPs or other LEOs.

Not my specialty, but I'll be bumping into some MPs tomorrow (hopefully not before then ), and will try to remember to ask and post what I find.