I just went to abc.net.au -- watched a bit of the news. Seems there has been gunfire, and some injuries. The whole thing sounds terrible, the hostages must be absolutely terrified.
No point in being PC about this. It's an Iranian cleric of some sort, with a history of violence. It may offend some, but it doesn't change the fact that muslim extremists are behind much of the terrorism in the world.
I say muslim extremists, because I do believe that many ordinary muslim people are held hostage by fear of retaliation from extremists if they oppose them in any way.