(CNN) -- Israeli Prime Minister Benjamin Netanyahu warned Sunday that the United States must establish a clear "red line" that Iran cannot cross with its nuclear program if it wants to avoid war.
"I think the issue is how to prevent Iran from completing its nuclear weapons program. They're moving very rapidly to completing the enrichment of the uranium that they need to produce a nuclear bomb. In six months or so, they will be 90% of the way there," Netanyahu said on CNN's "State of the Union."
"I think it's important to place a red line before Iran, and I think that actually reduces the chance of a military conflict because, 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," Netanyahu told CNN's Candy Crowley.
Concerns in Washington that Israel could launch a pre-emptive strike on Iran's nuclear facilities prompted a wave of visits this summer to Israel by several top Obama administration officials.
Gen. Mohammad Ali Jafari, commander of Iran's Islamic Revolutionary Guard Corps, warned Sunday, "Our answer to the Zionist regime is quite clear. In the event of an attack on Iran by the Zionist regime there will be nothing left of Israel."
He added, "Considering the size of Israel and its vulnerabilities and also because of the high number of our rockets, I don't think anywhere in Israel will be safe."
Iran denies that it aims to build a nuclear bomb, saying that its nuclear program is for energy and medical use.
U.S. President Barack Obama last week reportedly rejected Netanyahu's call to lay down a line that Iran could not cross.
According to The New York Times, during an hour-long telephone call between the two leaders, Obama did not embrace Netanyahu's proposal to set a limit on the size of Iran's stockpile of close-to-bomb-grade uranium and launch a military strike if Tehran exceeded it.
Netanyahu has shown growing impatience with what he says is a lack of clarity by the Obama administration on articulating red lines over Iran's nuclear ambitions.
The administration has resisted pressure to take that step.
"We share a grave concern about Iran pursuing a nuclear weapon," U.S. ambassador to the United Nations Susan Rice told "State of the Union" Sunday.
"We are determined to prevent that from happening. President Obama has been absolutely clear, and on this there's absolutely no daylight between the United States and Israel that we will do what it takes to prevent Iran from acquiring a nuclear weapon."
Steps the United States and other countries are taking to pressure Iran are working, Rice said.
"We have just seen the imposition of another layer of the toughest sanctions that have ever been imposed on a country," she said, adding that Iran's oil production and currency have both plummeted 40%.
"And this is only going to intensify, so we think that there's still considerable time for this pressure to work, but this is not an infinite window."
U.S. intelligence officials have said they do not believe Iran has decided to develop a nuclear weapon, even as evidence continues to mount that the country is improving its ability to do so.
Far from establishing a threshold for military action, the closest White House spokesman Jay Carney would go last week was to repeat the commonly-used phrase "the president is committed to prevent Iran from acquiring a nuclear weapon."
Atomic enrichment in and of itself is not a red line, a U.S. official told CNN following the telephone call between Obama and Netanyahu.
But Israel feels a sense of urgency, as negotiations aimed at curbing Iran's nuclear ambitions have failed to produce an agreement and sanctions have fallen short of their intended effect.
The issue has taken on a decidedly political tone with Netanyahu's call coming at the height of the presidential election season.
The prime minister told CNN that he knew people "are trying to draw me into the American election, and I'm not going to do that."
"But I will say that we value, we cherish the bipartisan support for Israel in the United States, and we're supported by Democrats and Republicans alike," he said.
"This is not an electoral issue. It is not based on any electoral consideration. I think that there's a common interest of all Americans, of all political persuasions, to stop Iran. This is a regime that is giving vent to the worst impulses that you see right now in the Middle East."