The gap between Israel and the United States on Iran widened Sunday as Benjamin Netanyahu insisted on a "red line" from Washington, claiming Tehran is "90 percent" toward having a nuclear bomb.

The Israeli leader, speaking on two US political television talkshows, pressed the need for a categorical bar on Iran, saying such a safeguard had averted nuclear calamity with Russia during the Cold War and could ensure peace again.

The United States says all options against Iran, including military action, remain on the table, but top officials reject so-called "red lines" as political grandstanding that might leave them at a strategic disadvantage.

On CNN and on NBC's "Meet the Press," Netanyahu maintained that telling Iran there is a definite line it must step back from would serve as a preemptive and effective deterrent.

"If they know there's a point, a stage in the enrichment or other nuclear activities that they cannot cross because they'll face consequences, I think they'll actually not cross it," he told CNN's "State of the Union."

"It's important to put a red line before them, and that's something we should discuss with the United States."

The Israeli prime minister said Iran was moving rapidly to complete enrichment of the uranium needed to produce a nuclear bomb. "In six months or so, they'll be 90 percent of the way there," he said.

But his call for a change of tack and stiffer warnings from Washington was rejected by Susan Rice, the US ambassador to the United Nations.

Rice, who spoke on five separate television talkshows, maintained there was "no daylight" between the US and Israel on preventing Iran from acquiring a nuclear weapon, but her comments on the timescale of Tehran's ambitions jarred with Netanyahu's judgment.

"We think that there's still considerable time for this pressure to work," Rice said, refusing to acknowledge the red lines argument and insisting that US sanctions were effectively hobbling Iran's currency and oil production.

But she added: "This is not an infinite window, and we've made very clear that the president's bottom line is Iran will not have a nuclear weapon."

Israel has consistently said a nuclear-armed Iran would pose an existential threat to the Jewish state and has wielded the threat of military action, but the United States favors sanctions and diplomatic arm-twisting.

Iran has steadfastly denied that it is seeking the bomb.

Relations between Netanyahu and President Barack Obama are viewed as frosty, and US Defense Secretary Leon Panetta further highlighted policy differences in an interview published Friday.

"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.

"That's the real world. Red lines are kind of political arguments that are used to try to put people in a corner."

The White House was forced in recent days to deny a report that Obama had refused to meet Netanyahu in New York later this month, and said the two spoke by telephone on Tuesday and were united in their stance toward Tehran.

With Republican presidential nominee Mitt Romney accusing Obama of being a poor friend to Israel, Netanyahu has denied that he is meddling in US politics ahead of elections on November 6.

Rice said that US-Israeli relations were "stronger than ever," and insisted the only reason Netanyahu and Obama would not meet at the upcoming UN General Assembly in New York was because their schedules did not match.

But Senator John McCain, the Republican presidential nominee who lost to Obama in 2008, said there was a clear gap between Israel and the White House on where the red line lies.

"In the administration's view, it's when (Iran) has a nuclear weapon," and in Israel's view, its when Tehran has reached the level where they can quickly assemble a nuclear weapon," McCain told CBS's "Face the Nation."

"That's a big difference," he said.

The threat of war, however, remains severe, according to Martin Indyk, a former US ambassador to Israel.

"I'm afraid that 2013 is going to be a year in which we're going to have a military confrontation with Iran," he said on "Face the Nation."