Presumptive Republican presidential nominee Mitt Romney would "respect" and back Israel if they decided to attack Iran to prevent the country from developing nuclear weapons, the candidate's campaign said on Sunday.

"If Israel has to take action on its own, in order to stop Iran from developing the capability, the governor would respect that decision," Romney's senior national security adviser Dan Senor told reporters, adding that a strike should be "on the table."

Romney arrived in Israel on Sunday, where Israeli Prime Minister Benjamin Netanyahu embraced him as a "personal friend and friend of Israel."

"We have to be honest and say that all the sanctions and diplomacy so far have not set back the Iranian program by one iota," Netanyahu said during his meeting with Romney. "And that's why I believe that we need a strong and credible military threat coupled with the sanctions to have a chance to change that situation."

President Barack Obama has said that he has "zero tolerance" for Iranian nuclear weapons, but has tried to convince Israel not to take military action.