30 to 42 civilians killed in a single blow. An accident? Apparently not. According to the IDF, they knew some civilians where there, but where trying to get Hamas militants who where among them. In addition the IDF confirms that it has instigated extra "aggressive" tactics "that create enormous damage on the ground". (See here.)
Anything else I could say has been said better by Richard Silverman on his Tikum Olam blog - read it here.