UPDATE II: One of the reasons given for the lack of confirmation at this point explains a lot about the war itself:
Hizbullah has a headquarters compound in Bourj al-Barajneh that is off limits to the Lebanese police and army, so security officials could not confirm the strike.
Got that? The Lebanese police and army are not allowed to enter onto its own land. That's not much of an excuse for a state, especially given that the land is in the capital city of Lebanon.