Yes, its illegal. There are plenty of cases where members of organized crime families (stand in for terrorists) have been convicted of illegal activities which harmed other members of the same or different organized crime family.<p>That said, if you do it under the guise of an intelligence operation then its ok apparently. Also you would be bound by jurisdictional laws, so if you did that in international waters I&#x27;m guessing you could make a case for it not being an issue.<p>Further, I doubt anyone would try to prosecute you for pulling a fast one on terrorists, but the terrorist organization is by definition one that doesn&#x27;t respect the rule of law, borders, or individual human rights, so the lack of prosecution would be the least of your worries.