Iran has been Israel's main foe since 1979, when Ayatollah Ruhollah Khomeini deposed the Shah. Iran has vowed to eradicate the Jewish state.

The nuclear issue came up Thursday at an annual meeting with the Israel Editors' Committee in Tel Aviv.

Sharon stressed Israel and other countries "cannot accept a situation in which Iran will have a nuclear weapon. That is clear to us, known to us and we are also making all the preparations necessary in order to be ready for such situations."

The meeting with the editors is an annual event held around the anniversary of the Nov. 29, 1947, United Nations decision to partition Palestine into Jewish and Arab states. Shortly before the meeting, the Maariv newspaper ran a red banner headline quoting a "senior security source" as saying Israel by itself couldn't cope with Teheran.

"We shall have to put up with a nuclear Iran," the unnamed source said.

"I do not see any force in the world, today, that could reverse the situation -- namely Iran becoming nuclear ... and there will be no alternative but to put up with the emerging situation," he added.

Sharon suggested the editors be skeptical over reports by anonymous sources, though the context indicated the source was, indeed, high.

"Israel is not helpless and it is taking all the necessary steps," the prime minister asserted.

He did not go into detail, but in recent years Israel has acquired long-range F-15I aircraft, developed its Arrow anti ballistic missile system mainly to intercept missiles with nuclear warheads and has recently ordered two more Dolphin Class submarines from Germany. Foreign reports suggest the three German made submarines Israel already has give it a second-strike capability. That is, the ability to destroy the enemy even after absorbing his first strike. It launched spy satellites into space, indicating it has powerful missiles.

However, Sharon reiterated Israel's long-standing policy that stresses Israel is not at the forefront of the struggle with Iran.

"The danger is not only to Israel but to the Middle East and many other countries in the world," he said.

Israeli security sources have often noted that Iran is developing missiles that can reach Europe.

"That is why the effort underway today, with the U.S. leadership, is an effort that all the free states who understand the terrible danger (of a nuclear Iran) must share," Sharon said.

Israel is "in very close contact with other countries leading this struggle," he added.

Asked whether the international community has a military option, should all the diplomatic efforts fail to stop Iran, Sharon said: "Yes, definitely."

He said he was "sure that before anyone goes for such (military) steps, every effort would be made to pressure Iran to stop this activity."

In 1981 Israel destroyed Iraq's Osiraq reactor and thereby prevented Saddam Hussein from developing an Iraqi nuclear bomb, but Iran has learnt the lesson and reportedly dispersed and fortified its facilities.

Israel is particularly vulnerable to a nuclear attack because it is a small country (it is slightly smaller than New Jersey) and its population is concentrated in the center.

In a paper the Institute for Contemporary Affairs published in Jerusalem Thursday, professor Gerald Steinberg wrote, "There is no basis for accepting the Iranian claim that it is not seeking nuclear weapons or the assertion that a nuclear Iran is not dangerous."

Iran's leaders have repeatedly declared they aim to destroy Israel, he noted.

Iran's new president, Mahmoud Ahmadinejad, publicly repeated that threat in October 2005. "A few weeks earlier, the streets of Teheran were filled by missiles on parade, decorated with posters declaring the intention to "wipe Israel off the map," Steinberg wrote.

The diplomatic option is still a serious one largely because Iran "seeks to be part of the international community and not (be) a rogue state or a member of the 'axis of evil,'" he wrote.

International pressure has increased as India, whom Teheran considered a supporter, backed the International Atomic Energy Agency's decision in September, which said Iran has not complied with its obligations under the Nuclear Non-Proliferation Treaty. Russia and China, who had traditionally been Iran's allies, suddenly ceased to support it, Steinberg noted.

"The Iranian leadership has taken some measures and engaged in negotiations that only make sense when seen as efforts to avoid sanctions. It is also dependent to a degree on foreign technology for its nuclear weapons and missile development programs," Steinberg wrote.

Technically Iran's nuclear program includes developing a nuclear fuel cycle, and it seeks an ability to produce highly enriched uranium that is primarily useful for producing bombs, Steinberg wrote.

"In the Iranian case we have clear and detailed evidence of nuclear weapons efforts, not speculation or extrapolation. IAEA inspectors have samples of enriched uranium and other materials," Steinberg stressed.

"It could take two years, five years, or even 10," until Iran is seen as a de facto nuclear weapons state. It has reportedly been facing technical difficulties.

Nevertheless, Chief of Military Intelligence, Maj. Gen. Aharon Zeevi-Farkash, Wednesday reportedly told the Knesset Foreign Affairs and Defense Committee that Iran has already produced 45 tons of gas needed to make enriched uranium. The time for diplomatic efforts to bloc Iran's nuclear program is running out. In his address to the Cabinet Sunday, he reportedly spoke of few months before Iran makes a critical decision on how to move on with its research and development program.