UNITED NATIONS: Israeli Prime Minister Benjamin Netanyahu demanded Thursday that the international community impose a red line on Iran to prevent it from enriching enough uranium for a nuclear bomb.

“The hour is late, very late,” Netanyahu said, alleging Iran was already 70 per cent of the way through the process of enriching enough uranium to fuel a bomb, and must be prevented from reaching the 90 per cent level.

The Israeli leader even used the world stage at the UN to present a cardboard diagram of a bomb with different levels on it, drawing a thick red line across it with a marker pen for dramatic effect.

“Faced with a clear red line Iran will back down,” he said, insisting in a address to the United Nations General Assembly that imposing an ultimatum on Tehran would not provoke war but help prevent it.

Israel has warned that it could launch military action against Iran in order to prevent it reaching a certain nuclear threshold, and has urged the international community to force Tehran to abandon its atomic quest.

Iran denies it is building a nuclear weapon and has dismissed the Israeli threat.

US President Barack Obama vowed in his address to the United Nations on Tuesday that he would prevent Iran from getting the bomb but his administration has repeatedly rejected imposing a red line on Tehran.

“At stake is the future of the world,” Netanyahu said. “Nothing could imperil our future more than an Iran armed with nuclear weapons.

He recounted a long list of “terrorist” attacks which he blamed to Iran, and warned that “given this record of Iranian aggression without nuclear weapons, just imagine this aggression with nuclear weapons.

“If their terror networks armed with atomic bombs, who among you would feel safe in the Middle East? Who would be safe in Europe? Who would be safe in America? Who would be safe anywhere?” he asked.

And he warned that the international community could not rely on its own arsenals to deter Iranian aggression, denouncing Iranian leaders as religious fanatics who would be quite prepared to sacrifice their own population.

With relations between Netanyahu and Obama already viewed as frosty, US Defense Secretary Leon Panetta earlier this month highlighted the policy split further when he rejected Israel's “red lines” outright.

“The fact is, look, presidents of the United States, prime ministers of Israel or any other country, leaders of these countries don't have, you know, a bunch of little red lines that determine their decisions,” Panetta said.

“What they have are facts that are presented to them about what a country is up to, and then they weigh what kind of action is needed to be taken in order to deal with that situation,” he told Foreign Policy magazine.

“I mean, that's the real world. Red lines are kind of political arguments that are used to try to put people in a corner.”