Is this a declaration of war?

A few years ago in Australia, there was a case where a major bikie gang, openly attacked a police station. The police hold off the attack and then force the gang to retreat, with reinforcment from other police stations. While the Australia governent didn't do so, In my opinion what this biki gang did can be consider as a declaration of war on the state and if I'm in charge of Australia. I'll use this as an opportunity to declare this gang as enemy of the state and send in commandos, F16 and special forces, to wipe them out, if I have to. What is your opinion on this?