WASHINGTON, Oct 1: The United States and its allies must act to stop Iran’s nuclear program — by force if necessary because conventional diplomacy will not work, three senior Israeli lawmakers told reporters in Washington.

As a last resort Israel itself would act unilaterally to prevent Iran from acquiring nuclear arms, said the three legislators at a briefing at the Israeli embassy in Washington.

The lawmakers, who represent the ruling Likud as well as opposition parties, are visiting Washington to generate support for the Israeli position on the Iranian nuclear dispute.

This week they met senior US senators and congressmen as well as senior officials of the Bush administration and later told reporters that they highlighted the Iranian danger in all their meetings.

Asked if he thought the message got through, one of them said: “I did not get the feeling we were talking to the walls.”

Iran will not be deterred ‘by anything short of a threat of force’, said Arieh Eldad, a member of Israel’s right wing National Union Party, part of a delegation of Knesset members visiting Washington this week.

“They won’t be stopped unless they are convinced their programs will be destroyed if they continue,” he said.

Yuval Steinitz, chairman of the Knesset’s foreign affairs and defence committee, said the best hope was for the United States and other major powers to make it clear to Iranian leaders now there was ‘no chance they will ever see the fruits of a nuclear program’.

“Threats of sanctions and isolation alone will not do it,” said Mr Steinitz.

Yosef Lapid, head of the centrist opposition Shinui Party in the Knesset, added that Israel ‘will not live under the threat of an Iranian nuclear bomb’.

“We feel we are obliged to warn our friends that Israel should not be pushed into a situation where we see no other solution but to act unilaterally” against Iran, he said.

Mr Steinitz, a member of Prime Minister Ariel Sharon’s ruling Likud Party, stopped just short of a direct threat to bomb suspect Iranian nuclear sites.

Mr Steinitz said Israeli officials estimate that Tehran is only two to three years away from developing a nuclear bomb and that time was running out for the world to act.

“We see an Iranian bomb as a devastating, existential threat to Israel, to the entire Middle East, to all Western interests in the region,” he said.

“Despite all the different circumstances, we see similarities to what happened in the 1930s, when people underestimated the real problem or focused on other dangers. For us, either the world will tackle Iran in advance or all of us will face the consequences.”

The Bush administration has led the diplomatic campaign to pressure Iran, claiming the country for two decades has secretly pursued a nuclear arsenal.

Israel has acted unilaterally before to halt a nuclear program by its neighbours, bombing Iraq’s Osirak reactor in 1981.

Mr Eldad said Israelis across the political spectrum see Iran as the country’s most serious threat and one that cannot be ignored.

But he added that unilateral action by Israel was the ‘worst possible scenario’, likely to inflame opinion throughout the Muslim world.