I suppose it was done to make a point, hence the large viewing audience of officials, it wasn't so much a these guys have done anything wrong, more a dare to stand against me and this is your fate.....
Like all Dictators, life at the top has to be a constant fear that someone somewhere wants what you have. It's power through fear and suppression of the masses through force and constant brainwashing to make them see you as a God and why his predecessor travelled everywhere in an armoured train.