Israel's prime minister has said the policy of sanctions to try to halt Iran's nuclear programme will not work because Tehran is guided by a "leadership of fanaticism".
In an interview on NBC News, Benjamin Netanyahu said he also disagreed with those who argue that going to war with Iran would be worse than it having nuclear weapons.
"Iran is guided by a leadership with an unbelievable fanaticism," he said.
"You want these fanatics to have nuclear weapons?"
The top commander in Iran's Revolutionary Guard responded by warning that "nothing will remain" of Israel if it takes military action to target the nuclear programme.
General Mohammad Ali Jafari said a response to any attack would begin near the Israeli border and that oil shipments through the Strait of Hormuz would be in jeopardy if war broke out.
The US and Israel have both left open the possibility of a strike on Iran if sanctions and diplomacy fails to stop a suspected push for a nuclear weapon.
The rhetoric from both sides has raised the spectre of conflict in the Middle East after a spate of cyber attacks on Iranian nuclear facilities and the killings of nuclear scientists in the country.
Tehran insists the nuclear programme is for peaceful purposes.
Brigadier General Mike Herzog, a former Israeli defence chief, told Sky's Dermot Murnaghan: "Israel is considering a strike on Iran, that's no secret we have been saying it for quite a while.
"The question is for the Israeli government should we move independently before the window of opportunity for Israel closes or should we wait and give the US the chance to do the right thing.
"There is a sense of urgency because the feeling is sanctions and diplomacy do not yield results."
Dr Pippa Malmgren, former White House adviser, said US bunker buster missiles were not delivered to Israel in August and joint military exercises with the US were scaled down.
"The Iranians are speeding up and putting 1,000 new centrifuges in," she said.
"The US under President Obama is not going to be of any assistance (to Israel) in any way. That has changed."