The U.S. is "not setting deadlines" for Iran and still considers negotiations to be "by far the best approach" to prevent Iran from developing nuclear weapons, U.S. Secretary of State Hillary Clinton told Bloomberg in an interview published Monday.

Speaking to Bloomberg Radio on Sunday after the conclusion of meetings at an Asia-Pacific forum in Vladivostok, Russia, Clinton said that economic sanctions are affecting Iran and the U.S. is "watching very carefully about what [the Iranians] do, because it's always been more about their actions than their words."

Her comments were published just hours after Republican presidential candidate Mitt Romney slammed President Barack Obama's policy on Iran, dubbing it his "greatest failure."

Last week, Prime Minister Benjamin Netanyahu said that the international community was not doing enough to slow Iran's nuclear progress. "This is a brutal regime that is racing ahead with its nuclear program because it doesn't see a clear red line from the international community and it doesn't see the necessary resolve and determination from the international community," Netanyahu said.

Israel believes that Iran's nuclear program could be stopped if Obama would clearly demand that Iran immediately halt its uranium enrichment program and set a date for inspection of its nuclear facilities. If Iran does not meet these demands, the U.S. should then take military action, according to Israel. Netanyahu thinks that making such a strong statement would force Iran to choose between nuclear aspirations and the current regime's survival.

Asked if the Obama administration would set sharper "red lines" for Iran or explicitly state the consequences for failing to reach a solution in nuclear negotiations with the Iranians, Clinton told Bloomberg, "We're not setting deadlines."

While the U.S. and Israel are both determined that Iran not acquire a nuclear weapon, Clinton said there is a difference in perspective over the time frame for talks.

“They’re [the Israelis] more anxious about a quick response because they feel that they’re right in the bull’s-eye, so to speak,” Clinton told Bloomberg. “But we’re convinced that we have more time to focus on these sanctions, to do everything we can to bring Iran to a good-faith negotiation.”

There was no immediate response to Clinton's comments from the Prime Minister's Office on Monday morning, Army Radio reported.

Meanwhile, Republican presidential candidate Mitt Romney slammed Obama's policy on Iran in an interview with NBC's "Meet the Press" on Sunday, calling it his "greatest failure." "The president has not drawn us further away from a nuclear Iran," he said, "In fact, Iran is closer to having a weapon, closer to having nuclear capability than when he took office. This is the greatest failure, in my opinion, of his foreign policy."

He said that the current administration's policy has not stopped Iranian President Mahmoud Ahmadinejad from progressing toward nuclear armament and that a military response to Iran should always remain an option.

He said, “President Obama had a policy of engagement with Ahmadinejad. That policy has not worked and we're closer to a nuclear weapon as a result of that. I will have a very different approach with regards to Iran. And it's an approach which, by the way, the president's finally getting closer to. It begins with crippling sanctions. That should have been put in place long ago.”

Romney acknowledged that the United States was “in some ways safer” because of Obama’s leadership, noting the assassination of al-Qaida leader Osama bin Laden as one example.

“I think Iran, however, becoming nuclear is a whole different development and a game changing, threatening development,” he said. “Threatening not only to our ally, Israel, but threatening the United States of America. And the president has not been successful. And in the words of Prime Minister Netanyahu, ‘Iran has not changed its nuclear course one iota by virtue of this president's policies.’ And that's something I intend to change.”

Romney said that the world could not live with a nuclear Iran. “I think we make it very clear that a nuclear Iran is unacceptable to the United States of America, to civilized nations throughout the world. And that we will maintain every option that's available to us to keep that from happening.”

When asked by host David Gregory why he may succeed with Iran when Presidents Obama and George W. Bush did not, Romney responded, “Well, at the time President Bush was president, Iran was years away from a nuclear weapon. And he pursued diplomacy, as I can think we should continue to pursue diplomatic channels. We should pursue as well the kind of crippling sanctions that I've spoken about when I gave a speech at the Herzliya Conference five years ago. We need to use every resource we have to dissuade them from their nuclear path. But that doesn't mean that we would take off the table our military option. That's something which certainly every American would hope we would never have to use. But we have to maintain it on the table or Iran will, undoubtedly, continue their treacherous course.”