We should also keep in mind that the whole reason they're saying this to begin with is because we've already gone into their country, killed some dudes, blew some shit up, then balled the fuck out before they had any time to react. Unless they want to try and convince us that this one time was just a fluke and that they're really, super duper serious about confronting us next time, I'd chalk this up to them talking big but with little substance to back it up.