Folks,
Iran has repeatedly stated it's intention to obliterate Israel. Whether or not Israel has nuclear weapons of it's own is not "public" knowledge, but mostly highly informed speculation as there has never been a test of such a weapon that would prove they have one.

This is in all probability an attempt to secure the Jewish vote and any swing voters who don't feel that Obama is strong enough on national security (He has stated that he'd meet with the leaders of the countries which still regard Israel as a target rather than a country, something our current leadership won't do).

Considering we do have treaties with Israel that we will defend her as an ally, I don't think her statement is much of a surprise.