WASHINGTON U.S. Secretary of State Hillary Clinton said on Sunday that Iran would not be allowed to have a nuclear weapon and reiterated Washington's commitment to protect close ally Israel from any threat posed by Tehran.
"We are going to do everything we can to prevent you (Iran) from getting a nuclear weapon. Your pursuit is futile," she told NBC's "Meet the Press" program, adding that Iran did not have the right to develop a nuclear weapon.
Clinton annoyed ally Israel last week by saying the United States would cope with a nuclear Iran by arming its allies in the Gulf and extending a "defense umbrella" over the region.
A senior Israeli official said the United States should focus on preventing Iran from getting a nuclear weapon rather than talking as if this may be a fait accompli.
Asked whether she had been referring to a nuclear umbrella, Clinton told NBC: "We are not talking in specifics, because that would come later if at all. My view is you hope for the best, but plan for the worst," said Clinton.
"Clearly, we have a long, durable relationship with Israel. We believe strongly that Israel's security must be protected," she added.
Major powers suspect Iran is seeking to build a nuclear bomb. Tehran maintains its nuclear work is a civilian program to generate much-needed electrical power.
Several senior U.S. officials, including Defense Secretary Robert Gates and national security advisor James Jones, will be in Israel this week, seeking to reassure the Jewish state amid concerns it could strike first against Iran if it believes there is no global resolve to curb Tehran's nuclear plans.
"Our message (to Israel) is as it has been. The United States stands with you and the United States believes that Israel has a right to security. We believe, however, that this (diplomatic) approach we are taking, holds out the promise of realizing our common objective," said Clinton.
The Obama administration fears an Israeli strike against Iran would further destabilize the region and have dramatic consequences.
Asked for her views on a preemptive Israeli strike against Iran, Clinton reiterated Israel's right to defend itself and said it would not listen to other nations if it believed its survival were threatened.
But she stressed that pursuing intensive diplomacy with Iran was the best approach, a shift from the Bush administration which avoided engagement with Tehran and insisted that Tehran give up sensitive nuclear work first.
"We will continue to work with all of our allies, and most particularly Israel, to determine the best way forward to prevent Iran from becoming a nuclear state," she said.
The Obama administration and several European allies such as France have threatened a new round of financial sanctions against Iran by the end of the year if it does not agree to give up uranium enrichment.
Clinton said major powers would make very clear to Iran what the costs of pursuing their nuclear ambitions would be.
So far, U.S. diplomatic outreach with Tehran has failed to produce any results and Clinton said this month that confusion following Iran's disputed election made the country's intentions even less clear.
Clinton said she had been "moved" by Iranian protesters' actions following the June election.
"Clearly, we would hope better for the Iranian people, we would hope that there is more openness and that peaceful demonstrations are respected," she said, criticizing the Iranian government's quelling of dissent.
(Additional reporting by Alister Bull; editing by Anthony Boadle)