UPDATE 1-Iran warns Israel of "last breath" if it attacks

(Adds comment on millions of volunteers, background)

TEHRAN, Sept 28 (Reuters) - Iran's defence minister warned arch-foe Israel on Monday against launching any attack on the Islamic Republic, saying it would only speed up the Jewish state's own demise.

"If this happens, which of course we do not foresee, its ultimate result would be that it expedites the Zionist regime's last breath," Defence Minister Ahmad Vahidi said on state television.

He made the comment after Iran said it had test-fired missiles with ranges that could put Israel and U.S. bases in the region within striking distance.

Israeli leaders have repeatedly expressed alarm over Iran's nuclear ambitions and refused to rule out pre-emptive military action to stop Iran developing an atomic weapon.

Iran, which says its nuclear work is for peaceful power generation, has often shrugged off the possibility of any such strikes.

Vahidi, a former Revolutionary Guards commander, said that in the event of an Israeli attack its "lifespan, which is today coming to an end, would be speeded up."

He added that the "Zionist regime", the term Iran uses for Israel, was on a "slope of destruction".

Iran's hardline president, Mahmoud Ahmadinejad, has also repeatedly predicted Israel's downfall.

On Saturday, Israeli Foreign Minister Avigdor Lieberman said a newly disclosed nuclear facility in Iran was proof the Islamic Republic was seeking nuclear weapons, and called on the world to make an "unequivocal" response.

Israel, widely assumed to be the Middle East's sole nuclear power, has described Iran's uranium enrichment as a threat to its existence. It says "all options" are on the table in preventing Tehran from building nuclear missiles.

The head of Iran's Civil Defence Organisation, which is affiliated to the Revolutionary Guards, said 10 million members of a volunteer Islamic militia, Basij, were ready to defend Iran against any attacker.

"(That is why) no one would dare to aggress against it ... One million (members of) the Basij force can move to the country's borders within the smallest notice," Commander Qolam-Reza Jalali was quoted as saying by the Guards' website. (Reporting by Hossein Jaseb and Hashem Kalantari; writing by Fredrik Dahl; Editing by Charles Dick)