My deepest sympathies for all the people from the USA, especially for those, whose wifes, men, children, relatives or friends were victims of this incredible act.
There is NOTHING in the world that could justify or excuse such a terrible crime.
This is not only an assault against the United States of America - this is an assault against the whole mankind, against the humanity. Hate and fanaticism have produced this unbelievable massacre. We all feel helpless now and some may think about revenge, but even if it's hard to imagine now : there must be another way to stand up against this terror than preaching violence and hate...