The Iranian threat to Israel is substantive but not existential, according to former Mossad Chief Ephraim Halevy.

During a lecture in Jerusalem yesterday, Halevy said "the State of Israel cannot be destroyed."

He also called on the government to follow Washington's lead and offer Iran a diplomatic option, in parallel with stepping up efforts to foil Tehran's nuclear plan.

Halevy's lecture presented a less-disturbing picture from the one offered by President George W. Bush.

"Israel cannot be destroyed for many reasons, some of which are known and others you can presume, Halevy said. "There is a chance that something serious will happen here, but I tend to say the following when I am abroad: Israel cannot be destroyed. If you do not believe this, the don't, but I suggest that you do not try it."

According to Halevy, during the Second Lebanon War, Israel managed to strike at the Iranian efforts that started about 25 years ago, to establish a "foothold" from which to aim not only against Israel but also against Europe.

"Iran was on the verge of a strategic gain of the first degree, and with one sweep, the Iranian foothold in Lebanon suffered a very serious blow," he said. "One of the great achievements of the war was the destruction of the [Hezbollah's long range] missile arsenal and of Iran's strategic capabilities [there]. It was one of the more successful operations of the air force and of Israeli intelligence."

Halevy says that the inability of Iran to respond to a blow "right between their eyes" shows that "they are no giants."

As for Russia's ties with Iran, Halevy suggested that President Vladimir Putin "is very much aware of the implications of a nuclear Iran and I am certain he does not want this." The former Mossad head said that in spite the strategic partnership between them, Moscow is becoming increasingly concerned about the domestic implications of a more powerful Iran.

Halevy discussed the change in American policy toward Iran, as expressed by Secretary of State Condoleezza Rice in March 2006. According to Rice, the U.S. would be willing to hold talks with Tehran if it froze its nuclear program.

"We must deal with Iran in parallel ways," he said. "Do everything possible to make it harder on them, undermine their efforts through economic measures and international sanctions, and on the other hand come to them and say 'if you change your ways - there are things we can talk about,'" Halevy said.