US Republican presidential nominee Mitt Romney slammed US President Barack Obama's handling of the Iranian threat on Sunday, saying "Iran has not changed its nuclear course one iota by virtue of this president's policies."

However, when pressed during an interview on NBC's "Meet the Press" to detail exactly what would constitute a "red line" that would trigger US military action against Iran's nuclear facilities in a Romney administration, including the potential deployment of US ground troops, the Republican nominee's answers appeared similar to those of Obama administration officials.

"I don't think we 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."

Romney criticized Obama for starting his presidency with a policy of "engaging" Iranian President Mahmoud Ahmadinejad, but added that the president had since toughened his Iran policy, a move in the right direction.

"President Obama had a policy of engagement...I will have a very different approach with regards to Iran, it's an approach, by the way, that the president's finally getting closer to, and that begins with crippling sanctions, that should have been put in place long ago."

Click here for special JPost coverage

While Romney called Iran "Obama's greatest foreign policy failure," he said that he would continue along the path of diplomacy with Iran.

"We should continue to pursue diplomatic channels...but that does not mean we should take off the table our military option, that's something that 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."

Romney said that a nuclear Iran would be "threatening not only to our ally Israel, but threatening to the United States of America. The president has not been successful, and in the words of Prime Minister [Binyamin] 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."

The Republican nominee expressed confidence in his electoral standing, following the Republican and Democratic conventions in the past two weeks.

"Now that both sides have made their argument, there is a big choice to make...I'm in a better spot than I was before the convention," he stated.

A Reuters/Ipsos poll released Saturday showed Obama picking up support following the conventions, widening his narrow lead over Romney by four percentage points.

Please LIKE our Facebook page - it makes us stronger